diff --git a/data/json/obsolete.json b/data/json/obsolete.json
index 9b6cfa2acd2c5..04eced3ada5f7 100644
--- a/data/json/obsolete.json
+++ b/data/json/obsolete.json
@@ -727,7 +727,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "forging_standard", 2 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "GRIND", "level": 2 } ],
@@ -748,7 +748,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -769,7 +769,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -790,7 +790,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -811,7 +811,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -832,7 +832,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 16 ], [ "steel_standard", 4 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -853,7 +853,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 16 ], [ "steel_standard", 4 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -874,7 +874,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 10 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -895,7 +895,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 4 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -916,7 +916,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 16 ], [ "steel_standard", 4 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -937,7 +937,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -958,7 +958,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -979,7 +979,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 20 ], [ "steel_standard", 5 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
diff --git a/data/json/proficiencies/chemistry.json b/data/json/proficiencies/chemistry.json
index 8979e487d829f..dbd710fa111cf 100644
--- a/data/json/proficiencies/chemistry.json
+++ b/data/json/proficiencies/chemistry.json
@@ -7,7 +7,7 @@
     "description": "You are beginning to grasp a general idea of how elements and compounds react with each other.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "12 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "You are beginning to gain a general idea of how various living beings function.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "12 h"
   },
   {
@@ -29,7 +29,7 @@
     "description": "Knowledge of the branch of chemistry that studies and uses carbon-containing compounds.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_intro_chemistry" ],
     "time_to_learn": "8 h"
   },
@@ -41,7 +41,7 @@
     "description": "Knowledge of the branch of chemistry that studies and uses compounds not containing carbon.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_intro_chemistry" ],
     "time_to_learn": "8 h"
   },
@@ -53,7 +53,7 @@
     "description": "The understanding of the chemistry of living things.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_organic_chemistry", "prof_intro_biology" ],
     "time_to_learn": "8 h",
     "default_weakpoint_bonus": 2,
@@ -67,7 +67,7 @@
     "description": "An in-depth understanding of how humans and animals operate.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_intro_biology" ],
     "time_to_learn": "12 h",
     "default_weakpoint_bonus": 2,
@@ -81,7 +81,7 @@
     "description": "You are beginning to grasp a general idea of how alien and post-Cataclysm mutated creatures function and operate.",
     "can_learn": true,
     "default_time_multiplier": 2.0,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "required_proficiencies": [ "prof_intro_biology" ],
     "time_to_learn": "12 h",
     "default_weakpoint_bonus": 4,
@@ -95,7 +95,7 @@
     "description": "You're beginning to grasp the basics of chemical production.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "required_proficiencies": [ "prof_intro_chemistry" ],
     "time_to_learn": "12 h"
   },
@@ -107,7 +107,7 @@
     "description": "The proper understanding of safe chemical synthesization and how to clean your tools used for the next batch.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_intro_chem_synth" ],
     "time_to_learn": "16 h"
   },
@@ -119,7 +119,7 @@
     "description": "The process of separating two mixed liquids by their different boiling points.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h"
   },
   {
@@ -130,7 +130,7 @@
     "description": "An understanding of the chemistry of metalworking and alloys.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "6 h"
   },
   {
@@ -141,7 +141,7 @@
     "description": "An understanding of how to produce various natural and chemical substances pure enough for human consumption.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_intro_chemistry", "prof_intro_biology" ],
     "time_to_learn": "8 h"
   }
diff --git a/data/json/proficiencies/comestibles.json b/data/json/proficiencies/comestibles.json
index 5e1641c4b2719..71c8d071f8fc1 100644
--- a/data/json/proficiencies/comestibles.json
+++ b/data/json/proficiencies/comestibles.json
@@ -7,7 +7,7 @@
     "description": "You've done enough cooking to know the basics about how to quickly and efficiently sort your ingredients.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1,
+    "default_skill_penalty": 0,
     "time_to_learn": "6 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "You're quite skilled at culinary knife work, making you noticeably faster at preparing meals that involve a lot of chopping.",
     "can_learn": true,
     "default_time_multiplier": 1.25,
-    "default_fail_multiplier": 1,
+    "default_skill_penalty": 0,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_food_prep" ]
   },
@@ -30,7 +30,7 @@
     "description": "You know the basics of baking - proportions, leavening, and things - and are less likely to make a dramatic mistake when working from memory.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "10 h"
   },
   {
@@ -41,7 +41,7 @@
     "description": "You've baked enough bread to consider yourself an expert.  May your yeast be ever frothy.",
     "can_learn": true,
     "default_time_multiplier": 1.25,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "6 h",
     "required_proficiencies": [ "prof_baking" ]
   },
@@ -53,7 +53,7 @@
     "description": "Anyone can make a cookie, but you can make it look amazing.  Cakes and other fluffies are also no longer a barrier.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "4 h",
     "required_proficiencies": [ "prof_baking" ]
   },
@@ -65,7 +65,7 @@
     "description": "You could have been a professional baker before the Cataclysm.  Your profiteroles are the envy of the wastelands.",
     "can_learn": true,
     "default_time_multiplier": 1.25,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_baking_desserts_1" ]
   },
@@ -77,7 +77,7 @@
     "description": "Anyone can toss stuff into deep fryer oil.  You know more about selecting oil, keeping the food from burning, and the like.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.1,
+    "default_skill_penalty": 0.1,
     "time_to_learn": "2 h"
   },
   {
@@ -88,7 +88,7 @@
     "description": "You know enough about deep frying breads and batters to do it easily without thinking about it.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.1,
+    "default_skill_penalty": 0.1,
     "time_to_learn": "4 h",
     "required_proficiencies": [ "prof_frying" ]
   },
@@ -100,7 +100,7 @@
     "description": "You know the vaunted secrets of creating delicious deep fried sweets.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.1,
+    "default_skill_penalty": 0.1,
     "time_to_learn": "4 h",
     "required_proficiencies": [ "prof_frying", "prof_baking_desserts_1" ]
   },
@@ -112,7 +112,7 @@
     "description": "The basics of fermenting for human consumption, including sanitary technique, avoiding harmful molds, and identifying common problems.",
     "can_learn": true,
     "default_time_multiplier": 1.25,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "10 h"
   },
   {
@@ -123,7 +123,7 @@
     "description": "Applying the science of distillation to alcoholic beverages to get something tasty.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_distilling" ]
   },
@@ -135,7 +135,7 @@
     "description": "The fine art of brewing grains into beers.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_fermenting" ]
   },
@@ -147,7 +147,7 @@
     "description": "The knowledge of how to turn sugary fruits, and occasionally vegetables, into fermented beverages.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_fermenting" ]
   },
@@ -159,7 +159,7 @@
     "description": "The microbiology of most non-alcoholic fermented edibles, from sauerkraut to sourdough.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_fermenting" ]
   },
@@ -171,7 +171,7 @@
     "description": "The basics of curdling and coagulating milk and similar things without the wrong kinds of bacteria and mold winning out.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h"
   },
   {
@@ -182,7 +182,7 @@
     "description": "Taking the basics of curdled milk and making it delicious.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_cheesemaking_1" ]
   },
@@ -194,7 +194,7 @@
     "description": "The basic knowledge of ways to keep food safe for long periods of time in a post-refrigeration world.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h"
   },
   {
@@ -205,7 +205,7 @@
     "description": "Using salt, smoke, and similar agents to cure or dehydrate food.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_preservation" ]
   },
@@ -217,7 +217,7 @@
     "description": "Using pressure canning or tinning to safely store food in sealed containers.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_preservation" ]
   },
@@ -229,7 +229,7 @@
     "description": "You know the secrets of cooking tasty food using strange substitutions and weird things you found in a cabinet in an abandoned house.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.1,
+    "default_skill_penalty": 0.1,
     "time_to_learn": "8 h"
   },
   {
@@ -240,7 +240,7 @@
     "description": "Cooking with foraged ingredients that you wouldn't find in most cookbooks.",
     "can_learn": true,
     "default_time_multiplier": 1.1,
-    "default_fail_multiplier": 1.1,
+    "default_skill_penalty": 0.1,
     "time_to_learn": "8 h"
   }
 ]
diff --git a/data/json/proficiencies/electronics.json b/data/json/proficiencies/electronics.json
index f5512515b4208..e895d59cd75a0 100644
--- a/data/json/proficiencies/electronics.json
+++ b/data/json/proficiencies/electronics.json
@@ -7,7 +7,7 @@
     "description": "An understanding of the skills and tools needed to create durable, effective soldered electrical connections.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "5 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "Practical experience building electrical circuits, and a grasp of the principles of electrical continuity, current, voltage, and resistance.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "10 h"
   },
   {
@@ -29,7 +29,7 @@
     "description": "Basic working knowledge of using semiconductors such as diodes and transistors in electrical circuits, for switching or amplifying electrical signals.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "required_proficiencies": [ "prof_elec_circuits" ],
     "time_to_learn": "12 h"
   },
@@ -41,7 +41,7 @@
     "description": "Familiarity with the role of IC chips in circuit design, and ability to identify many common pre-Cataclysm ICs and understand how to use them in functional circuits.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "required_proficiencies": [ "prof_elec_semiconductors" ],
     "time_to_learn": "16 h"
   },
@@ -53,7 +53,7 @@
     "description": "A practical working knowledge of electromagnetic fields and their creation and application.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h",
     "default_weakpoint_bonus": 2,
     "default_weakpoint_penalty": 0
@@ -66,7 +66,7 @@
     "description": "An understanding of how to use high voltage, low-current devices to cause debilitating muscle spasms.  Includes some theoretical knowledge of how to protect yourself from these.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "10 h"
   }
 ]
diff --git a/data/json/proficiencies/gunsmithing.json b/data/json/proficiencies/gunsmithing.json
index 567200f9f9697..1f7f531f466ad 100644
--- a/data/json/proficiencies/gunsmithing.json
+++ b/data/json/proficiencies/gunsmithing.json
@@ -7,7 +7,7 @@
     "description": "A basic understanding of how guns are put together and what tools and materials are needed for the job.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "4 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "You've become an expert at putting together guns and launchers from makeshift parts.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "//": "Intentionally does not require basic gunsmithing"
   },
@@ -30,7 +30,7 @@
     "description": "You're specifically skilled at building and repairing antique guns.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_metalworking", "prof_gunsmithing_basic" ]
   },
@@ -42,7 +42,7 @@
     "description": "Similar to bowyery, the art of making guns that are powered by elastic mechanisms.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "6 h"
   },
   {
@@ -53,7 +53,7 @@
     "description": "You've got the know-how to make a classic Western revolver, and its many variants.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_gunsmithing_basic" ]
   }
diff --git a/data/json/proficiencies/health_care.json b/data/json/proficiencies/health_care.json
index 13600f9ad8112..a19a430a509d9 100644
--- a/data/json/proficiencies/health_care.json
+++ b/data/json/proficiencies/health_care.json
@@ -7,7 +7,7 @@
     "description": "You know how to bandage wounds and understand basic principles of wound care.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "2 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "Your extensive field experience in bandaging and wound care is on par with that of a paramedic.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "14 h",
     "required_proficiencies": [ "prof_wound_care" ]
   },
@@ -30,7 +30,7 @@
     "description": "You have some basic understanding of how burns work and (potentially) how they could be treated.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "12 h",
     "default_weakpoint_bonus": 2,
     "default_weakpoint_penalty": 0
diff --git a/data/json/proficiencies/mechanics.json b/data/json/proficiencies/mechanics.json
index 8da6b2febb950..9d8a8f1a12b04 100644
--- a/data/json/proficiencies/mechanics.json
+++ b/data/json/proficiencies/mechanics.json
@@ -7,7 +7,7 @@
     "description": "Maintaining and building simple engines.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "You know how to safely and efficiently build, repair, maintain and use various appliances that make use of high pressure.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "12 h",
     "required_proficiencies": [ "prof_plumbing", "prof_basic_engines", "prof_appliance_repair", "prof_pneumatics" ]
   },
@@ -30,7 +30,7 @@
     "description": "You know how to safely and efficiently build, repair, maintain and use various complex machinery that makes use of chemical processes.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "20 h",
     "required_proficiencies": [ "prof_high_pressure_systems", "prof_chem_synth" ]
   },
@@ -42,7 +42,7 @@
     "description": "Maintaining and building compressed-air powered machines.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "8 h"
   }
 ]
diff --git a/data/json/proficiencies/metalwork.json b/data/json/proficiencies/metalwork.json
index 741e4b5a70e00..9698feb1a0abd 100644
--- a/data/json/proficiencies/metalwork.json
+++ b/data/json/proficiencies/metalwork.json
@@ -7,7 +7,7 @@
     "description": "A basic understanding of the properties of metal as a material, and the concepts behind smithing, die casting, and other metalworking techniques.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "2 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "A basic understanding of the different types of welding, welding tools and fuels, how to weld different materials, and more.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h",
     "required_proficiencies": [ "prof_metalworking" ]
   },
@@ -30,7 +30,7 @@
     "description": "You are an experienced welder.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_welding_basic" ]
   },
@@ -42,7 +42,7 @@
     "description": "The craft of working metal into tools and other items of use.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_metalworking" ]
   },
@@ -54,7 +54,7 @@
     "description": "Working copper and bronze shares a lot of techniques with blacksmithing, but the more ductile copper-containing metals have a trick all their own.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_metalworking" ]
   },
@@ -66,7 +66,7 @@
     "description": "How to make jewelry from precious metals like gold and silver.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "time_to_learn": "14 h"
   },
   {
@@ -77,7 +77,7 @@
     "description": "How to make articulated armor from pieces of metal.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "12 h",
     "required_proficiencies": [ "prof_blacksmithing" ]
   },
@@ -89,7 +89,7 @@
     "description": "How to fabricate sharp and reliable blades from scratch.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "12 h",
     "required_proficiencies": [ "prof_blacksmithing" ]
   },
@@ -101,7 +101,7 @@
     "description": "How to make high-quality tools and parts by hand.  Includes techniques like threading, durable articulation points, and using appropriate metals for appropriate tasks.  Also applies to making blunt instruments that can withstand a severe beating without distortion.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_blacksmithing" ]
   },
@@ -113,7 +113,7 @@
     "description": "How to turn raw ingots and metals into usable wire.  Includes both drawing and extruding.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_metalworking" ]
   },
@@ -125,7 +125,7 @@
     "description": "Heating steel packed in charcoal at high temperatures to cause a hard case of higher carbon steel around the lower carbon core.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "10 h"
   },
   {
@@ -136,7 +136,7 @@
     "description": "Quenching involves repeatedly heating the steel, quenching it in water, then tempering it to create extremely tough metal.",
     "can_learn": true,
     "default_time_multiplier": 3,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "20 h"
   }
 ]
diff --git a/data/json/proficiencies/misc.json b/data/json/proficiencies/misc.json
index a2bbc4efcc6f3..f62956a39a88b 100644
--- a/data/json/proficiencies/misc.json
+++ b/data/json/proficiencies/misc.json
@@ -7,7 +7,7 @@
     "description": "You know the basic principles of turning stones into more useful tools.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.8,
+    "default_skill_penalty": 0.8,
     "time_to_learn": "8 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "You've banged rocks together so much and for so long, you've become extremely fast at it.",
     "can_learn": true,
     "default_time_multiplier": 5,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "12 h",
     "required_proficiencies": [ "prof_knapping" ],
     "ignore_focus": true
@@ -31,7 +31,7 @@
     "description": "Working with glass and heat without poisoning or perforating yourself.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "8 h"
   },
   {
@@ -42,7 +42,7 @@
     "description": "Working with pipes and pipe fittings to transport fluids without leakage.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h"
   },
   {
@@ -53,7 +53,7 @@
     "description": "Basic pottery, from shaping to working with slip to fuse pieces.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h"
   },
   {
@@ -64,7 +64,7 @@
     "description": "The ability to make durable, effective bows.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "10 h"
   },
   {
@@ -75,7 +75,7 @@
     "description": "The skill involved in making arrows that fly true.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h"
   },
   {
@@ -86,7 +86,7 @@
     "description": "Forming coarse fibers into shapes.",
     "can_learn": true,
     "default_time_multiplier": 2.5,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "time_to_learn": "6 h"
   },
   {
@@ -97,7 +97,7 @@
     "description": "Adding glazes to pottery to make them waterproof.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "time_to_learn": "5 h"
   },
   {
@@ -108,7 +108,7 @@
     "description": "Working with plastic using your hands, including carving, molding, and gluing it.  You know how to identify thermoplastics that are suitable for mold casting, and how to identify the right plastic for the right job.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h"
   },
   {
@@ -119,7 +119,7 @@
     "description": "Shaping wood, bone, and similar materials with a cutting implement.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "time_to_learn": "10 h"
   },
   {
@@ -146,7 +146,7 @@
     "description": "How to add gemstones to jewelry.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_fine_metalsmithing", "prof_redsmithing" ]
   },
@@ -158,7 +158,7 @@
     "description": "You know how to accurately measure powder and projectile weights for reloading firearm cartridges.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "8 h"
   },
   {
@@ -178,7 +178,7 @@
     "description": "A base knowledge of how to put together and take apart common appliances, diagnose problems, and replace parts.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.1,
+    "default_skill_penalty": 0.1,
     "time_to_learn": "8 h"
   }
 ]
diff --git a/data/json/proficiencies/tailoring.json b/data/json/proficiencies/tailoring.json
index 6790735ede5ed..b17ecb0c7a099 100644
--- a/data/json/proficiencies/tailoring.json
+++ b/data/json/proficiencies/tailoring.json
@@ -8,7 +8,7 @@
     "//": "while specifically made for tailoring, I think this could also apply to things like making robot legs.  For tailoring this is mostly a speed boost skill.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "6 h"
   },
   {
@@ -19,7 +19,7 @@
     "description": "You are familiar with the adjustments and tricks needed to make properly functional buttons, zippers, and other closures on garments.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "6 h"
   },
   {
@@ -30,7 +30,7 @@
     "description": "You know how to make garments and fabric containers sealed against water.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "//": "The 'closures' part of the name is historical."
   },
@@ -42,7 +42,7 @@
     "description": "Making elastic bands is easy enough, but making a whole garment from stretchy cloth takes a bit of finesse.  You're good at it.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "6 h"
   },
   {
@@ -54,7 +54,7 @@
     "can_learn": true,
     "time_to_learn": "10 h",
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "required_proficiencies": [ "prof_closures", "prof_leatherworking_basic" ]
   },
   {
@@ -66,7 +66,7 @@
     "//": "In the future, having this proficiency could give a boost to learning rope making and vice versa",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "6 h"
   },
   {
@@ -77,7 +77,7 @@
     "description": "You've learned how to use a loom to produce sheets of fabric from thread.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.4,
+    "default_skill_penalty": 0.4,
     "time_to_learn": "6 h"
   },
   {
@@ -88,7 +88,7 @@
     "description": "Like a solitary mouse, you've learned how to construct hats by hand.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_leatherworking_basic" ]
   },
@@ -100,7 +100,7 @@
     "description": "Knitting, one of the oldest ways of tying knots in fiber until it is fabric.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "8 h"
   },
   {
@@ -111,7 +111,7 @@
     "description": "You have knitted and knitted and knitted some more, and have the consistent string tension to show for it.  When you get going, the clicking of your needles is like a metronome.",
     "can_learn": true,
     "default_time_multiplier": 5,
-    "default_fail_multiplier": 1,
+    "default_skill_penalty": 0,
     "time_to_learn": "20 h",
     "required_proficiencies": [ "prof_knitting" ],
     "ignore_focus": true
@@ -124,7 +124,7 @@
     "description": "You've got a basic familiarity with how to work with leather, furs, hides, and similar materials.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "4 h"
   },
   {
@@ -135,7 +135,7 @@
     "description": "Working with leather requires a specific set of skills and tools… a set you are familiar with.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h",
     "required_proficiencies": [ "prof_leatherworking_basic" ]
   },
@@ -147,7 +147,7 @@
     "description": "Working with fur and faux fur is a skill all its own.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_leatherworking_basic" ]
   },
@@ -160,7 +160,7 @@
     "//": "Given that nobody has ever written a guide for this, it should be particularly tough to master.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "16 h",
     "required_proficiencies": [ "prof_leatherworking_basic" ]
   },
@@ -172,7 +172,7 @@
     "description": "Turning sheets of chain links into effective, wearable clothing that doesn't bind up.",
     "can_learn": true,
     "default_time_multiplier": 3,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "10 h"
   },
   {
@@ -183,7 +183,7 @@
     "description": "You know the tricks for working with Kevlar, Nomex, and other advanced polymer cloth.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h"
   }
 ]
diff --git a/data/json/proficiencies/traps.json b/data/json/proficiencies/traps.json
index 6d881c1b7e250..8894f7fc8f23e 100644
--- a/data/json/proficiencies/traps.json
+++ b/data/json/proficiencies/traps.json
@@ -7,7 +7,7 @@
     "description": "You know how to pick a lock, at least in theory.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "time_to_learn": "2 h"
   },
   {
@@ -18,7 +18,7 @@
     "description": "You can pick a lock in the dark, blindfolded.  Although that doesn't make it all that much harder.  You're good at locks, OK?",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "14 h",
     "required_proficiencies": [ "prof_lockpicking" ]
   },
@@ -30,7 +30,7 @@
     "description": "Opening safes is an exacting skill, one that you are proficient at.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "10 h"
   },
   {
@@ -41,7 +41,7 @@
     "description": "You know the basics of setting and taking down traps safely.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.25,
+    "default_skill_penalty": 0.25,
     "time_to_learn": "3 h"
   },
   {
@@ -52,7 +52,7 @@
     "description": "You're specifically quite skilled at setting effective traps.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_traps" ]
   },
@@ -64,7 +64,7 @@
     "description": "You know how to take down a trap safely.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "8 h",
     "required_proficiencies": [ "prof_traps" ]
   },
@@ -76,7 +76,7 @@
     "description": "You are skilled at spotting things out of the ordinary, like traps or ambushes.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "3 h"
   }
 ]
diff --git a/data/json/proficiencies/wilderness.json b/data/json/proficiencies/wilderness.json
index 59d131f66af05..f4108b5a12dce 100644
--- a/data/json/proficiencies/wilderness.json
+++ b/data/json/proficiencies/wilderness.json
@@ -7,7 +7,7 @@
     "description": "You've got a basic grasp of the theory of how to twist and arrange fibers into a more durable cord.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5,
+    "default_skill_penalty": 0.5,
     "//": "Experimental data: I actually went camping and just sat around twisting cordage until I felt like I had a good handle on it.",
     "time_to_learn": "4 h"
   },
@@ -20,7 +20,7 @@
     "can_learn": true,
     "time_to_learn": "8 h",
     "default_time_multiplier": 3,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "required_proficiencies": [ "prof_fibers" ]
   },
   {
@@ -32,7 +32,7 @@
     "can_learn": true,
     "time_to_learn": "4 h",
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.5
+    "default_skill_penalty": 0.5
   },
   {
     "type": "proficiency",
@@ -43,7 +43,7 @@
     "can_learn": true,
     "time_to_learn": "8 h",
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "required_proficiencies": [ "prof_tanning_basic" ]
   },
   {
@@ -55,7 +55,7 @@
     "can_learn": true,
     "time_to_learn": "5 h",
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "bonuses": { "archery": [ { "type": "strength", "value": 1 } ] },
     "ignore_focus": true
   },
@@ -68,7 +68,7 @@
     "can_learn": true,
     "time_to_learn": "10 h",
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "required_proficiencies": [ "prof_bow_basic" ],
     "bonuses": { "archery": [ { "type": "strength", "value": 1 } ] },
     "ignore_focus": true
@@ -82,7 +82,7 @@
     "can_learn": true,
     "time_to_learn": "20 h",
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "required_proficiencies": [ "prof_bow_expert" ],
     "bonuses": { "archery": [ { "type": "strength", "value": 1 } ] },
     "ignore_focus": true
diff --git a/data/json/proficiencies/woodworking.json b/data/json/proficiencies/woodworking.json
index a956faa4f7747..1aeecd0aa1d1a 100644
--- a/data/json/proficiencies/woodworking.json
+++ b/data/json/proficiencies/woodworking.json
@@ -7,7 +7,7 @@
     "description": "Simple projects involving holding planks and panels of wood together with nails or similar fasteners.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.15,
+    "default_skill_penalty": 0.15,
     "time_to_learn": "4 h"
   }
 ]
diff --git a/data/json/recipes/appliances/oven.json b/data/json/recipes/appliances/oven.json
index cc955bf799ea8..b48878cfd1435 100644
--- a/data/json/recipes/appliances/oven.json
+++ b/data/json/recipes/appliances/oven.json
@@ -30,7 +30,7 @@
     "time": "45 m",
     "skill_used": "fabrication",
     "qualities": [ { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_appliance_repair", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_appliance_repair", "skill_penalty": 0 } ],
     "components": [
       [ [ "oven_stovetop", 1 ] ],
       [ [ "oven_cabinet", 1 ] ],
@@ -48,7 +48,7 @@
     "activity_level": "MODERATE_EXERCISE",
     "time": "30 m",
     "skill_used": "fabrication",
-    "proficiencies": [ { "proficiency": "prof_appliance_repair", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_appliance_repair", "skill_penalty": 0 } ],
     "qualities": [
       { "id": "SCREW", "level": 1 },
       { "id": "WRENCH", "level": 1 },
@@ -63,7 +63,7 @@
     "activity_level": "MODERATE_EXERCISE",
     "time": "1 h",
     "skill_used": "fabrication",
-    "proficiencies": [ { "proficiency": "prof_appliance_repair", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_appliance_repair", "skill_penalty": 0 } ],
     "qualities": [
       { "id": "SCREW", "level": 1 },
       { "id": "WRENCH", "level": 1 },
@@ -92,7 +92,7 @@
     "activity_level": "MODERATE_EXERCISE",
     "time": "1 h",
     "skill_used": "fabrication",
-    "proficiencies": [ { "proficiency": "prof_appliance_repair", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_appliance_repair", "skill_penalty": 0 } ],
     "qualities": [
       { "id": "SCREW", "level": 1 },
       { "id": "WRENCH", "level": 1 },
@@ -116,7 +116,7 @@
     "activity_level": "MODERATE_EXERCISE",
     "time": "30 m",
     "skill_used": "fabrication",
-    "proficiencies": [ { "proficiency": "prof_appliance_repair", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_appliance_repair", "skill_penalty": 0 } ],
     "qualities": [
       { "id": "SCREW", "level": 1 },
       { "id": "WRENCH", "level": 1 },
@@ -132,8 +132,8 @@
     "time": "1 h",
     "skill_used": "fabrication",
     "proficiencies": [
-      { "proficiency": "prof_elec_soldering", "fail_multiplier": 1 },
-      { "proficiency": "prof_elec_circuits", "fail_multiplier": 1 }
+      { "proficiency": "prof_elec_soldering", "skill_penalty": 0 },
+      { "proficiency": "prof_elec_circuits", "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "SCREW", "level": 1 } ],
     "tools": [ [ [ "soldering_iron", -1 ], [ "toolset", -1 ] ] ],
diff --git a/data/json/recipes/armor/arms.json b/data/json/recipes/armor/arms.json
index 530fc38120f77..e75ccfd7e2768 100644
--- a/data/json/recipes/armor/arms.json
+++ b/data/json/recipes/armor/arms.json
@@ -198,7 +198,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 },
       { "proficiency": "prof_articulation" }
     ]
   },
@@ -419,7 +419,7 @@
     "using": [ [ "cordage", 1 ], [ "mixed_steel", 1 ] ],
     "components": [ [ [ "cotton_patchwork", 6 ] ] ],
     "qualities": [ { "id": "HAMMER", "level": 1 }, { "id": "SAW_M", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 }, { "proficiency": "prof_articulation" } ]
+    "proficiencies": [ { "proficiency": "prof_armorsmithing", "skill_penalty": 0 }, { "proficiency": "prof_articulation" } ]
   },
   {
     "result": "xs_armguard_scrap",
@@ -594,7 +594,7 @@
     "using": [ [ "armor_lc_chainmail_assembling", 3 ], [ "tailoring_cotton_patchwork", 8 ] ],
     "proficiencies": [
       { "proficiency": "prof_chain_armour", "required": false, "time_multiplier": 3 },
-      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "skill_penalty": 0.15 }
     ]
   },
   {
@@ -628,7 +628,7 @@
     "using": [ [ "armor_mc_chainmail_assembling", 3 ], [ "tailoring_cotton_patchwork", 8 ] ],
     "proficiencies": [
       { "proficiency": "prof_chain_armour", "required": false, "time_multiplier": 3 },
-      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "skill_penalty": 0.15 }
     ]
   },
   {
@@ -662,7 +662,7 @@
     "using": [ [ "armor_hc_chainmail_assembling", 3 ], [ "tailoring_cotton_patchwork", 8 ] ],
     "proficiencies": [
       { "proficiency": "prof_chain_armour", "required": false, "time_multiplier": 3 },
-      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "skill_penalty": 0.15 }
     ]
   },
   {
@@ -696,7 +696,7 @@
     "using": [ [ "armor_ch_chainmail_assembling", 3 ], [ "tailoring_cotton_patchwork", 8 ] ],
     "proficiencies": [
       { "proficiency": "prof_chain_armour", "required": false, "time_multiplier": 3 },
-      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "skill_penalty": 0.15 }
     ]
   },
   {
@@ -730,7 +730,7 @@
     "using": [ [ "armor_qt_chainmail_assembling", 3 ], [ "tailoring_cotton_patchwork", 8 ] ],
     "proficiencies": [
       { "proficiency": "prof_chain_armour", "required": false, "time_multiplier": 3 },
-      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_articulation", "required": false, "time_multiplier": 2, "skill_penalty": 0.15 }
     ]
   },
   {
@@ -877,10 +877,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -917,10 +917,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -957,10 +957,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -997,7 +997,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -1041,11 +1041,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -1082,10 +1082,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1122,10 +1122,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1162,10 +1162,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1202,7 +1202,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -1246,11 +1246,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -1287,10 +1287,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1327,10 +1327,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1367,10 +1367,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1407,7 +1407,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -1451,11 +1451,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
diff --git a/data/json/recipes/armor/feet.json b/data/json/recipes/armor/feet.json
index cb0d4ddc915df..792365568b82b 100644
--- a/data/json/recipes/armor/feet.json
+++ b/data/json/recipes/armor/feet.json
@@ -1295,10 +1295,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1370,10 +1370,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1410,10 +1410,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1451,10 +1451,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -1493,10 +1493,10 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_quenching" }
     ]
   },
diff --git a/data/json/recipes/armor/hands.json b/data/json/recipes/armor/hands.json
index 6088c70a89792..09cf2907b3943 100644
--- a/data/json/recipes/armor/hands.json
+++ b/data/json/recipes/armor/hands.json
@@ -593,8 +593,8 @@
         "proficiency": "prof_closures",
         "required": false,
         "time_multiplier": 1.5,
-        "fail_multiplier": 1.15,
-        "learning_time_multiplier": 0.25
+        "learning_time_multiplier": 0.25,
+        "skill_penalty": 0.15
       },
       { "proficiency": "prof_articulation" }
     ],
@@ -1118,10 +1118,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1158,10 +1158,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1198,10 +1198,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1239,10 +1239,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -1281,10 +1281,10 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_quenching" }
     ]
   },
@@ -1322,10 +1322,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1397,10 +1397,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1437,10 +1437,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1478,10 +1478,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -1520,10 +1520,10 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_quenching" }
     ]
   },
diff --git a/data/json/recipes/armor/head.json b/data/json/recipes/armor/head.json
index 092d76f176c9c..867bb734bc380 100644
--- a/data/json/recipes/armor/head.json
+++ b/data/json/recipes/armor/head.json
@@ -1052,7 +1052,7 @@
     "using": [ [ "cordage", 1 ], [ "mixed_steel", 1 ] ],
     "components": [ [ [ "cotton_patchwork", 4 ] ] ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 } ]
+    "proficiencies": [ { "proficiency": "prof_armorsmithing", "skill_penalty": 0 } ]
   },
   {
     "result": "helmet_scrap_xs",
@@ -2696,10 +2696,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2726,10 +2726,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2756,10 +2756,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2786,10 +2786,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -2817,10 +2817,10 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_quenching" }
     ]
   },
diff --git a/data/json/recipes/armor/legs.json b/data/json/recipes/armor/legs.json
index 8bbfc895f4bb0..1388c91bbf8f8 100644
--- a/data/json/recipes/armor/legs.json
+++ b/data/json/recipes/armor/legs.json
@@ -67,7 +67,7 @@
     "time": "30 m",
     "autolearn": true,
     "book_learn": [ [ "mag_tailor", 1 ], [ "manual_tailor", 1 ] ],
-    "proficiencies": [ { "proficiency": "prof_elastics", "time_multiplier": 1.25, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_elastics", "time_multiplier": 1.25, "skill_penalty": 0.15 } ],
     "using": [ [ "tailoring_lycra_patchwork", 1 ] ]
   },
   {
@@ -1374,10 +1374,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1404,10 +1404,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1434,10 +1434,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1469,7 +1469,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -1502,11 +1502,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -1533,10 +1533,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1563,10 +1563,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1593,10 +1593,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1628,7 +1628,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -1661,11 +1661,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -1692,10 +1692,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1722,10 +1722,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1752,10 +1752,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -1787,7 +1787,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -1820,11 +1820,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
diff --git a/data/json/recipes/armor/pets_cow.json b/data/json/recipes/armor/pets_cow.json
index 6e0a743168d2e..cead661c068e7 100644
--- a/data/json/recipes/armor/pets_cow.json
+++ b/data/json/recipes/armor/pets_cow.json
@@ -54,7 +54,7 @@
     "proficiencies": [
       { "proficiency": "prof_chain_armour" },
       { "proficiency": "prof_closures" },
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 }
     ]
   },
   {
@@ -238,7 +238,7 @@
     "book_learn": [ [ "textbook_tailor", 5 ], [ "tailor_portfolio", 5 ], [ "textbook_armwest", 4 ], [ "textbook_armschina", 4 ] ],
     "using": [ [ "sewing_standard", 302 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -260,7 +260,7 @@
     "using": [ [ "forging_standard", 144 ], [ "bronzesmithing_tools", 12 ] ],
     "components": [ [ [ "scrap_bronze", 72 ] ], [ [ "leather_armor_cow", 1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_redsmithing" },
@@ -280,7 +280,7 @@
     "using": [ [ "blacksmithing_standard", 960 ], [ "steel_standard", 240 ], [ "fabric_leather_fur_hide", 36 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
diff --git a/data/json/recipes/armor/pets_dog.json b/data/json/recipes/armor/pets_dog.json
index e9e6c3d2830f8..8668b72aec767 100644
--- a/data/json/recipes/armor/pets_dog.json
+++ b/data/json/recipes/armor/pets_dog.json
@@ -54,7 +54,7 @@
     "proficiencies": [
       { "proficiency": "prof_chain_armour" },
       { "proficiency": "prof_closures" },
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 }
     ]
   },
   {
@@ -69,7 +69,7 @@
     "byproducts": [ [ "leather", 3 ] ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
     "components": [ [ [ "vest_leather", 1 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 } ]
+    "proficiencies": [ { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 } ]
   },
   {
     "result": "leather_harness_dog",
diff --git a/data/json/recipes/armor/pets_horse.json b/data/json/recipes/armor/pets_horse.json
index e4d5987bf2da9..6d4b8ae0f0c02 100644
--- a/data/json/recipes/armor/pets_horse.json
+++ b/data/json/recipes/armor/pets_horse.json
@@ -54,7 +54,7 @@
     "proficiencies": [
       { "proficiency": "prof_chain_armour" },
       { "proficiency": "prof_closures" },
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 }
     ]
   },
   {
@@ -238,7 +238,7 @@
     "book_learn": [ [ "textbook_tailor", 5 ], [ "tailor_portfolio", 5 ], [ "textbook_armwest", 4 ], [ "textbook_armschina", 4 ] ],
     "using": [ [ "sewing_standard", 260 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -260,7 +260,7 @@
     "using": [ [ "forging_standard", 120 ], [ "bronzesmithing_tools", 10 ] ],
     "components": [ [ [ "scrap_bronze", 60 ] ], [ [ "leather_armor_horse", 1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_redsmithing" },
@@ -280,7 +280,7 @@
     "using": [ [ "blacksmithing_standard", 800 ], [ "steel_standard", 200 ], [ "fabric_leather_fur_hide", 30 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
diff --git a/data/json/recipes/armor/suit.json b/data/json/recipes/armor/suit.json
index 155392f5fdfbd..fb264bf6134cb 100644
--- a/data/json/recipes/armor/suit.json
+++ b/data/json/recipes/armor/suit.json
@@ -184,7 +184,7 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "steel_standard", 20 ], [ "tailoring_leather_patchwork", 8 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -225,9 +225,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "cuirass_lightplate", 1 ] ], [ [ "armguard_lightplate", 1 ] ], [ [ "legguard_lightplate", 1 ] ] ]
   },
@@ -245,9 +245,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "xl_cuirass_lightplate", 1 ] ], [ [ "xl_armguard_lightplate", 1 ] ], [ [ "xl_legguard_lightplate", 1 ] ] ]
   },
@@ -275,7 +275,7 @@
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -315,7 +315,7 @@
     "using": [ [ "sewing_standard", 26 ] ],
     "qualities": [ { "id": "HAMMER", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -361,7 +361,7 @@
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -427,10 +427,7 @@
     "autolearn": true,
     "book_learn": [ [ "recipe_melee", 2 ] ],
     "using": [ [ "cordage", 2 ] ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_articulation", "skill_penalty": 0 } ],
     "components": [ [ [ "cuirass_scrap", 1 ] ], [ [ "armguard_scrap", 1 ] ], [ [ "legguard_scrap", 1 ] ] ]
   },
   {
@@ -668,8 +665,8 @@
     "book_learn": [ [ "dieselpunk_tailor", 2 ] ],
     "using": [ [ "cordage", 1 ] ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 }
     ],
     "components": [ [ [ "cuirass_tire", 1 ] ], [ [ "armguard_tire", 1 ] ], [ [ "legguard_tire", 1 ] ] ]
   },
@@ -892,10 +889,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "lc_chainmail_hood", 1 ] ], [ [ "lc_chainmail_hauberk", 1 ] ], [ [ "lc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -911,10 +905,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xl_lc_chainmail_hood", 1 ] ], [ [ "xl_lc_chainmail_hauberk", 1 ] ], [ [ "xl_lc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -930,10 +921,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xs_lc_chainmail_hood", 1 ] ], [ [ "lc_chainmail_hauberk_xs", 1 ] ], [ [ "xs_lc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -993,10 +981,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "mc_chainmail_hood", 1 ] ], [ [ "mc_chainmail_hauberk", 1 ] ], [ [ "mc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1012,10 +997,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xl_mc_chainmail_hood", 1 ] ], [ [ "xl_mc_chainmail_hauberk", 1 ] ], [ [ "xl_mc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1031,10 +1013,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xs_mc_chainmail_hood", 1 ] ], [ [ "mc_chainmail_hauberk_xs", 1 ] ], [ [ "xs_mc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1094,10 +1073,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "hc_chainmail_hood", 1 ] ], [ [ "hc_chainmail_hauberk", 1 ] ], [ [ "hc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1113,10 +1089,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xl_hc_chainmail_hood", 1 ] ], [ [ "xl_lc_chainmail_hauberk", 1 ] ], [ [ "xl_hc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1132,10 +1105,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xs_hc_chainmail_hood", 1 ] ], [ [ "hc_chainmail_hauberk_xs", 1 ] ], [ [ "xs_hc_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1195,10 +1165,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "ch_chainmail_hood", 1 ] ], [ [ "ch_chainmail_hauberk", 1 ] ], [ [ "ch_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1214,10 +1181,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xl_ch_chainmail_hood", 1 ] ], [ [ "xl_ch_chainmail_hauberk", 1 ] ], [ [ "xl_ch_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1233,10 +1197,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xs_ch_chainmail_hood", 1 ] ], [ [ "ch_chainmail_hauberk_xs", 1 ] ], [ [ "xs_ch_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1296,10 +1257,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "qt_chainmail_hood", 1 ] ], [ [ "qt_chainmail_hauberk", 1 ] ], [ [ "qt_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1315,10 +1273,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xl_qt_chainmail_hood", 1 ] ], [ [ "xl_qt_chainmail_hauberk", 1 ] ], [ [ "xl_qt_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1334,10 +1289,7 @@
     "reversible": true,
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
-    "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_chain_armour", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_closures", "skill_penalty": 0 }, { "proficiency": "prof_chain_armour", "skill_penalty": 0 } ],
     "components": [ [ [ "xs_qt_chainmail_hood", 1 ] ], [ [ "qt_chainmail_hauberk_xs", 1 ] ], [ [ "xs_qt_chainmail_legs", 1 ] ] ]
   },
   {
@@ -1881,12 +1833,12 @@
     "autolearn": true,
     "using": [ [ "sewing_kevlar", 200 ], [ "blacksmithing_standard", 10 ], [ "mc_steel_standard", 3 ], [ "fabric_lycra", 20 ] ],
     "proficiencies": [
-      { "proficiency": "prof_elastics", "fail_multiplier": 1.2, "time_multiplier": 1.3 },
-      { "proficiency": "prof_closures", "fail_multiplier": 1.1, "time_multiplier": 1.1 },
+      { "proficiency": "prof_elastics", "time_multiplier": 1.3, "skill_penalty": 0.2 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.1, "skill_penalty": 0.1 },
       { "proficiency": "prof_closures_waterproofing" },
       { "proficiency": "prof_polymerworking" },
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1.1, "time_multiplier": 1.1 },
+      { "proficiency": "prof_articulation", "time_multiplier": 1.1, "skill_penalty": 0.1 },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_quenching" }
@@ -2224,7 +2176,7 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "lc_steel_standard", 20 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2256,9 +2208,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_lc_light_chestplate", 1 ] ], [ [ "armor_lc_lightarmguard", 2 ] ], [ [ "armor_lc_light_leg_guard", 2 ] ] ]
   },
@@ -2276,9 +2228,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_lc_light_chestplate", 1 ] ],
@@ -2299,7 +2251,7 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "mc_steel_standard", 20 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2331,9 +2283,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_mc_light_chestplate", 1 ] ], [ [ "armor_mc_lightarmguard", 2 ] ], [ [ "armor_mc_light_leg_guard", 2 ] ] ]
   },
@@ -2351,9 +2303,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_mc_light_chestplate", 1 ] ],
@@ -2374,7 +2326,7 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "hc_steel_standard", 20 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2406,9 +2358,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_hc_light_chestplate", 1 ] ], [ [ "armor_hc_lightarmguard", 2 ] ], [ [ "armor_hc_light_leg_guard", 2 ] ] ]
   },
@@ -2426,9 +2378,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_hc_light_chestplate", 1 ] ],
@@ -2449,7 +2401,7 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "lc_steel_standard", 20 ], [ "tailoring_leather_patchwork", 3 ], [ "carbon", 5 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2487,9 +2439,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_ch_light_chestplate", 1 ] ], [ [ "armor_ch_lightarmguard", 2 ] ], [ [ "armor_ch_light_leg_guard", 2 ] ] ]
   },
@@ -2507,9 +2459,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_ch_light_chestplate", 1 ] ],
@@ -2530,13 +2482,13 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "mc_steel_standard", 20 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_articulation" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -240 ], [ "water_clean", -240 ] ] ]
   },
@@ -2563,9 +2515,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_qt_light_chestplate", 1 ] ], [ [ "armor_qt_lightarmguard", 2 ] ], [ [ "armor_qt_light_leg_guard", 2 ] ] ]
   },
@@ -2583,9 +2535,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_qt_light_chestplate", 1 ] ],
@@ -2606,7 +2558,7 @@
     "using": [ [ "blacksmithing_standard", 96 ], [ "lc_steel_standard", 25 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2638,9 +2590,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_lc_chestplate", 1 ] ], [ [ "armor_lc_armguard", 2 ] ], [ [ "armor_lc_leg_guard", 2 ] ] ]
   },
@@ -2658,9 +2610,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "xl_armor_lc_chestplate", 1 ] ], [ [ "xl_armor_lc_armguard", 2 ] ], [ [ "xl_armor_lc_leg_guard", 2 ] ] ]
   },
@@ -2677,7 +2629,7 @@
     "using": [ [ "blacksmithing_standard", 96 ], [ "mc_steel_standard", 25 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2709,9 +2661,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_mc_chestplate", 1 ] ], [ [ "armor_mc_armguard", 2 ] ], [ [ "armor_mc_leg_guard", 2 ] ] ]
   },
@@ -2729,9 +2681,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "xl_armor_mc_chestplate", 1 ] ], [ [ "xl_armor_mc_armguard", 2 ] ], [ [ "xl_armor_mc_leg_guard", 2 ] ] ]
   },
@@ -2748,7 +2700,7 @@
     "using": [ [ "blacksmithing_standard", 96 ], [ "hc_steel_standard", 25 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2780,9 +2732,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_hc_chestplate", 1 ] ], [ [ "armor_hc_armguard", 2 ] ], [ [ "armor_hc_leg_guard", 2 ] ] ]
   },
@@ -2800,9 +2752,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "xl_armor_hc_chestplate", 1 ] ], [ [ "xl_armor_hc_armguard", 2 ] ], [ [ "xl_armor_hc_leg_guard", 2 ] ] ]
   },
@@ -2819,7 +2771,7 @@
     "using": [ [ "blacksmithing_standard", 96 ], [ "lc_steel_standard", 25 ], [ "tailoring_leather_patchwork", 3 ], [ "carbon", 5 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -2857,9 +2809,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_ch_chestplate", 1 ] ], [ [ "armor_ch_armguard", 2 ] ], [ [ "armor_ch_leg_guard", 2 ] ] ]
   },
@@ -2877,9 +2829,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "xl_armor_ch_chestplate", 1 ] ], [ [ "xl_armor_ch_armguard", 2 ] ], [ [ "xl_armor_ch_leg_guard", 2 ] ] ]
   },
@@ -2896,13 +2848,13 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "mc_steel_standard", 20 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_articulation" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -240 ], [ "water_clean", -240 ] ] ]
   },
@@ -2929,9 +2881,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_qt_chestplate", 1 ] ], [ [ "armor_qt_armguard", 2 ] ], [ [ "armor_qt_leg_guard", 2 ] ] ]
   },
@@ -2949,9 +2901,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "xl_armor_qt_chestplate", 1 ] ], [ [ "xl_armor_qt_armguard", 2 ] ], [ [ "xl_armor_qt_leg_guard", 2 ] ] ]
   },
@@ -2968,7 +2920,7 @@
     "using": [ [ "blacksmithing_standard", 115 ], [ "lc_steel_standard", 30 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -3000,9 +2952,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_lc_heavy_chestplate", 1 ] ], [ [ "armor_lc_heavyarmguard", 2 ] ], [ [ "armor_lc_heavy_leg_guard", 2 ] ] ]
   },
@@ -3020,9 +2972,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_lc_heavy_chestplate", 1 ] ],
@@ -3043,7 +2995,7 @@
     "using": [ [ "blacksmithing_standard", 115 ], [ "mc_steel_standard", 30 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -3075,9 +3027,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_mc_heavy_chestplate", 1 ] ], [ [ "armor_mc_heavyarmguard", 2 ] ], [ [ "armor_mc_heavy_leg_guard", 2 ] ] ]
   },
@@ -3095,9 +3047,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_mc_heavy_chestplate", 1 ] ],
@@ -3118,7 +3070,7 @@
     "using": [ [ "blacksmithing_standard", 115 ], [ "hc_steel_standard", 30 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -3150,9 +3102,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_hc_heavy_chestplate", 1 ] ], [ [ "armor_hc_heavyarmguard", 2 ] ], [ [ "armor_hc_heavy_leg_guard", 2 ] ] ]
   },
@@ -3170,9 +3122,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_hc_heavy_chestplate", 1 ] ],
@@ -3193,7 +3145,7 @@
     "using": [ [ "blacksmithing_standard", 80 ], [ "lc_steel_standard", 30 ], [ "tailoring_leather_patchwork", 3 ], [ "carbon", 5 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -3231,9 +3183,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_ch_heavy_chestplate", 1 ] ], [ [ "armor_ch_heavyarmguard", 2 ] ], [ [ "armor_ch_heavy_leg_guard", 2 ] ] ]
   },
@@ -3251,9 +3203,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_ch_heavy_chestplate", 1 ] ],
@@ -3274,13 +3226,13 @@
     "using": [ [ "blacksmithing_standard", 115 ], [ "mc_steel_standard", 30 ], [ "tailoring_leather_patchwork", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_articulation" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -240 ], [ "water_clean", -240 ] ] ]
   },
@@ -3307,9 +3259,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [ [ [ "armor_qt_heavy_chestplate", 1 ] ], [ [ "armor_qt_heavyarmguard", 2 ] ], [ [ "armor_qt_heavy_leg_guard", 2 ] ] ]
   },
@@ -3327,9 +3279,9 @@
     "autolearn": true,
     "flags": [ "NO_RESIZE" ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "fail_multiplier": 1 },
-      { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 },
-      { "proficiency": "prof_articulation", "fail_multiplier": 1 }
+      { "proficiency": "prof_closures", "skill_penalty": 0 },
+      { "proficiency": "prof_armorsmithing", "skill_penalty": 0 },
+      { "proficiency": "prof_articulation", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "xl_armor_qt_heavy_chestplate", 1 ] ],
diff --git a/data/json/recipes/armor/torso.json b/data/json/recipes/armor/torso.json
index a1fd3d4b898bc..c1684fbf1bd32 100644
--- a/data/json/recipes/armor/torso.json
+++ b/data/json/recipes/armor/torso.json
@@ -121,7 +121,7 @@
     "time": "1 h",
     "autolearn": true,
     "book_learn": [ [ "mag_tailor", 1 ], [ "manual_tailor", 1 ] ],
-    "proficiencies": [ { "proficiency": "prof_elastics", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_elastics", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "using": [ [ "sewing_standard", 10 ], [ "tailoring_lycra_patchwork", 1 ] ]
   },
   {
@@ -138,8 +138,8 @@
     "byproducts": [ [ "scrap_fur", 2 ] ],
     "book_learn": [ [ "mag_animecon", 1 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.25, "fail_multiplier": 1.25 },
-      { "proficiency": "prof_furriery", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.25, "skill_penalty": 0.25 },
+      { "proficiency": "prof_furriery", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ]
   },
   {
@@ -513,10 +513,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -552,7 +552,7 @@
     "components": [ [ [ "cotton_patchwork", 8 ] ] ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 } ],
     "proficiencies": [
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_armorsmithing", "required": false, "time_multiplier": 1.5 }
     ]
   },
@@ -2166,8 +2166,8 @@
       {
         "proficiency": "prof_leatherworking_basic",
         "time_multiplier": 1.15,
-        "fail_multiplier": 1.15,
-        "learning_time_multiplier": 0.5
+        "learning_time_multiplier": 0.5,
+        "skill_penalty": 0.15
       }
     ]
   },
@@ -2240,8 +2240,8 @@
       {
         "proficiency": "prof_leatherworking_basic",
         "time_multiplier": 1.15,
-        "fail_multiplier": 1.15,
-        "learning_time_multiplier": 0.5
+        "learning_time_multiplier": 0.5,
+        "skill_penalty": 0.15
       }
     ]
   },
@@ -2522,10 +2522,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2552,10 +2552,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2582,10 +2582,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2612,10 +2612,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -2643,11 +2643,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -2674,10 +2674,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2704,10 +2704,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2734,10 +2734,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2764,10 +2764,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -2795,11 +2795,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -2826,10 +2826,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2856,10 +2856,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2886,10 +2886,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ]
   },
   {
@@ -2916,10 +2916,10 @@
     "tools": [ [ [ "swage", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
       { "proficiency": "prof_case_hardening" }
     ]
   },
@@ -2947,11 +2947,11 @@
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_armorsmithing" },
-      { "proficiency": "prof_closures", "time_multiplier": 1.25, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_closures", "time_multiplier": 1.25, "skill_penalty": 0.15 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 },
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
diff --git a/data/json/recipes/other/cords_and_ropes.json b/data/json/recipes/other/cords_and_ropes.json
index 3196d5e27f9ca..19716d9771887 100644
--- a/data/json/recipes/other/cords_and_ropes.json
+++ b/data/json/recipes/other/cords_and_ropes.json
@@ -69,7 +69,7 @@
     "time": "2 h",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1.5 }, { "proficiency": "prof_fibers_rope" } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0.5 }, { "proficiency": "prof_fibers_rope" } ],
     "components": [ [ [ "filament", 1800, "LIST" ] ] ]
   },
   {
@@ -85,7 +85,7 @@
     "reversible": true,
     "autolearn": true,
     "tools": [ [ [ "spinwheelitem", -1 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1.5 }, { "proficiency": "prof_fibers_rope" } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0.5 }, { "proficiency": "prof_fibers_rope" } ],
     "components": [ [ [ "filament", 1800, "LIST" ] ] ]
   },
   {
@@ -251,7 +251,7 @@
     "time": "10 h",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1.5 }, { "proficiency": "prof_fibers_rope" } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0.5 }, { "proficiency": "prof_fibers_rope" } ],
     "components": [ [ [ "filament", 10800, "LIST" ] ] ]
   },
   {
@@ -267,7 +267,7 @@
     "reversible": true,
     "autolearn": true,
     "tools": [ [ [ "spinwheelitem", -1 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1.5 }, { "proficiency": "prof_fibers_rope" } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0.5 }, { "proficiency": "prof_fibers_rope" } ],
     "components": [ [ [ "filament", 10800, "LIST" ] ] ]
   },
   {
@@ -532,7 +532,7 @@
     "reversible": true,
     "autolearn": true,
     "tools": [ [ [ "electric_spinwheel", 13 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1.5 }, { "proficiency": "prof_fibers_rope" } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0.5 }, { "proficiency": "prof_fibers_rope" } ],
     "components": [ [ [ "filament", 1800, "LIST" ] ] ]
   },
   {
@@ -630,7 +630,7 @@
     "reversible": true,
     "autolearn": true,
     "tools": [ [ [ "electric_spinwheel", 63 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1.5 }, { "proficiency": "prof_fibers_rope" } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0.5 }, { "proficiency": "prof_fibers_rope" } ],
     "components": [ [ [ "filament", 10800, "LIST" ] ] ]
   },
   {
diff --git a/data/json/recipes/other/materials.json b/data/json/recipes/other/materials.json
index 788df032661b5..d9a9289bf22ef 100644
--- a/data/json/recipes/other/materials.json
+++ b/data/json/recipes/other/materials.json
@@ -455,7 +455,7 @@
     "skills_required": [ "fabrication", 1 ],
     "time": "10 m",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_spinning", "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_spinning", "skill_penalty": 0.5 } ],
     "tools": [ [ [ "distaff_spindle", -1 ] ] ],
     "components": [ [ [ "cotton_ball", 3 ] ] ]
   },
@@ -470,7 +470,7 @@
     "skill_used": "tailor",
     "time": "30 s",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_spinning", "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_spinning", "skill_penalty": 0.5 } ],
     "tools": [ [ [ "spinwheelitem", -1 ] ] ],
     "components": [ [ [ "cotton_ball", 3 ] ] ]
   },
@@ -485,7 +485,7 @@
     "skill_used": "tailor",
     "time": "30 s",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_spinning", "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_spinning", "skill_penalty": 0.5 } ],
     "tools": [ [ [ "electric_spinwheel", 2 ] ] ],
     "components": [ [ [ "cotton_ball", 3 ] ] ]
   },
@@ -1109,7 +1109,7 @@
       { "id": "CUT", "level": 2 },
       { "id": "FILE", "level": 1 }
     ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.25, "fail_multiplier": 1.125 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.25, "skill_penalty": 0.125 } ],
     "components": [ [ [ "mop", 1 ], [ "stick", 1 ], [ "broom", 1 ] ], [ [ "wax", 1 ], [ "rosin", 1 ] ] ]
   },
   {
@@ -1259,7 +1259,7 @@
     "subcategory": "CSC_OTHER_MATERIALS",
     "skill_used": "fabrication",
     "time": "30 minutes",
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1, "time_multiplier": 2 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 2, "skill_penalty": 0 } ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
     "components": [ [ [ "2x4", 1 ] ] ],
     "byproducts": [ [ "splinter", 5 ] ],
diff --git a/data/json/recipes/other/parts.json b/data/json/recipes/other/parts.json
index 8ab9df8ca5ca3..d3f4afa92aece 100644
--- a/data/json/recipes/other/parts.json
+++ b/data/json/recipes/other/parts.json
@@ -331,7 +331,7 @@
     "using": [ [ "welding_standard", 10 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "sheet_metal_small", 24 ] ] ]
@@ -364,7 +364,7 @@
     "using": [ [ "welding_standard", 6 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "material_aluminium_ingot", 3 ], [ "scrap_aluminum", 34 ] ] ]
@@ -690,7 +690,7 @@
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
     "proficiencies": [
       { "proficiency": "prof_metalworking", "required": false, "time_multiplier": 1.5 },
-      { "proficiency": "prof_plumbing", "required": false, "time_multiplier": 3, "fail_multiplier": 1.5 }
+      { "proficiency": "prof_plumbing", "required": false, "time_multiplier": 3, "skill_penalty": 0.5 }
     ],
     "components": [ [ [ "pipe", 1 ] ], [ [ "scrap", 1 ] ], [ [ "plastic_chunk", 1 ] ], [ [ "pipe_fittings", 1 ] ] ]
   },
@@ -709,7 +709,7 @@
     "using": [ [ "rope_natural", 4 ], [ "welding_standard", 10 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
@@ -729,7 +729,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
@@ -749,7 +749,7 @@
     "using": [ [ "sewing_standard", 50 ], [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "pipe", 4 ] ], [ [ "spring", 2 ] ], [ [ "cotton_patchwork", 20 ], [ "sheet", 1 ] ], [ [ "pipe_fittings", 4 ] ] ]
@@ -768,7 +768,7 @@
     "using": [ [ "sewing_standard", 50 ], [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" },
       { "proficiency": "prof_leatherworking_basic" },
       { "proficiency": "prof_leatherworking" }
@@ -794,7 +794,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
@@ -873,7 +873,7 @@
     "difficulty": 6,
     "time": "2 h 30 m",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_plasticworking", "time_multiplier": 1.25, "fail_multiplier": 1.125 } ],
+    "proficiencies": [ { "proficiency": "prof_plasticworking", "time_multiplier": 1.25, "skill_penalty": 0.125 } ],
     "using": [ [ "surface_heat", 10 ] ],
     "qualities": [ { "id": "FILE", "level": 1 }, { "id": "CUT", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
     "components": [ [ [ "chunk_rubber", 8 ] ], [ [ "superglue", 4 ], [ "bone_glue", 4 ] ], [ [ "wheel_caster", 1 ] ] ]
@@ -899,7 +899,7 @@
     "skill_used": "survival",
     "time": "2 m",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_knapping", "time_multiplier": 1.25, "fail_multiplier": 1.1 } ],
+    "proficiencies": [ { "proficiency": "prof_knapping", "time_multiplier": 1.25, "skill_penalty": 0.1 } ],
     "qualities": [ { "id": "HAMMER", "level": 1 } ],
     "components": [ [ [ "rock_flaking", 1 ] ] ]
   }
diff --git a/data/json/recipes/other/parts_construction.json b/data/json/recipes/other/parts_construction.json
index f1649a149bfa8..787b1ea05d6d3 100644
--- a/data/json/recipes/other/parts_construction.json
+++ b/data/json/recipes/other/parts_construction.json
@@ -504,8 +504,8 @@
     "autolearn": true,
     "using": [ [ "welding_standard", 10 ] ],
     "proficiencies": [
-      { "proficiency": "prof_glassblowing", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.15 },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 }
+      { "proficiency": "prof_glassblowing", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.15 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 } ],
     "components": [ [ [ "reinforced_glass_pane", 4 ] ] ]
@@ -523,7 +523,7 @@
     "using": [ [ "welding_standard", 4 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 } ],
diff --git a/data/json/recipes/other/parts_rigs.json b/data/json/recipes/other/parts_rigs.json
index 28649a8898928..fd4fa188fff60 100644
--- a/data/json/recipes/other/parts_rigs.json
+++ b/data/json/recipes/other/parts_rigs.json
@@ -137,7 +137,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
@@ -157,7 +157,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
@@ -177,7 +177,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
@@ -197,7 +197,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
diff --git a/data/json/recipes/other/power_supplies.json b/data/json/recipes/other/power_supplies.json
index 84adb8906c6f7..50007aac35297 100644
--- a/data/json/recipes/other/power_supplies.json
+++ b/data/json/recipes/other/power_supplies.json
@@ -14,7 +14,7 @@
     "proficiencies": [
       { "proficiency": "prof_elec_soldering" },
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 } ],
@@ -34,7 +34,7 @@
     "using": [ [ "welding_standard", 4 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 } ],
@@ -54,7 +54,7 @@
     "using": [ [ "welding_standard", 4 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 } ],
@@ -75,7 +75,7 @@
     "proficiencies": [
       { "proficiency": "prof_elec_soldering" },
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 } ],
@@ -97,7 +97,7 @@
     "proficiencies": [
       { "proficiency": "prof_elec_soldering" },
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "sheet_metal", 1 ] ], [ [ "scrap", 2 ] ], [ [ "circuit", 1 ] ] ]
diff --git a/data/json/recipes/practice/athletics.json b/data/json/recipes/practice/athletics.json
index 027cd57a595ad..93767d0a26f15 100644
--- a/data/json/recipes/practice/athletics.json
+++ b/data/json/recipes/practice/athletics.json
@@ -40,7 +40,7 @@
     "autolearn": [ [ "swimming", 5 ] ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 3, "max_difficulty": 6, "skill_limit": 5 },
-    "proficiencies": [ { "proficiency": "prof_parkour", "fail_multiplier": 3, "time_multiplier": 2 } ],
+    "proficiencies": [ { "proficiency": "prof_parkour", "time_multiplier": 2, "skill_penalty": 2 } ],
     "flags": [ "BLIND_EASY" ],
     "tools": [ [ "parkour_practice" ] ]
   }
diff --git a/data/json/recipes/practice/devices.json b/data/json/recipes/practice/devices.json
index 332b3ca3cd019..39b93b34a11ff 100644
--- a/data/json/recipes/practice/devices.json
+++ b/data/json/recipes/practice/devices.json
@@ -9,7 +9,7 @@
     "description": "Practice picking simple locks.",
     "skill_used": "traps",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
-    "proficiencies": [ { "proficiency": "prof_lockpicking", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_lockpicking", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "tools": [ [ "lock" ] ],
     "//": "Crude picks will eventually lose their shape",
@@ -29,7 +29,7 @@
     "description": "Practice picking simple locks.",
     "skill_used": "traps",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
-    "proficiencies": [ { "proficiency": "prof_lockpicking", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_lockpicking", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "LOCKPICK", "level": 5 } ],
     "tools": [ [ "lock" ] ],
diff --git a/data/json/recipes/practice/electronics.json b/data/json/recipes/practice/electronics.json
index 040943c36bf7c..f617320701d9c 100644
--- a/data/json/recipes/practice/electronics.json
+++ b/data/json/recipes/practice/electronics.json
@@ -10,7 +10,7 @@
     "skill_used": "electronics",
     "time": "1 h",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 2 },
-    "proficiencies": [ { "proficiency": "prof_elec_soldering", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_elec_soldering", "time_multiplier": 1, "skill_penalty": 0 } ],
     "autolearn": [ [ "electronics", 1 ] ],
     "book_learn": [ [ "mag_electronics", 0 ], [ "manual_electronics", 0 ] ],
     "components": [ [ [ "cable", 5 ] ], [ [ "e_scrap", 2 ] ] ],
@@ -27,7 +27,7 @@
     "skill_used": "electronics",
     "time": "1 h",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
-    "proficiencies": [ { "proficiency": "prof_elec_circuits", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_elec_circuits", "time_multiplier": 1, "skill_penalty": 0 } ],
     "book_learn": [ [ "mag_electronics", 1 ], [ "manual_electronics", 1 ], [ "advanced_electronics", 2 ], [ "textbook_electronics", 3 ] ],
     "//": "Some parts are listed as tools so they are not destroyed during crafting, while the components are consumed.",
     "tools": [
@@ -51,7 +51,7 @@
     "practice_data": { "min_difficulty": 1, "max_difficulty": 3, "skill_limit": 4 },
     "proficiencies": [
       { "proficiency": "prof_elec_circuits", "required": true },
-      { "proficiency": "prof_elec_semiconductors", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_elec_semiconductors", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "book_learn": [ [ "manual_electronics", 1 ], [ "advanced_electronics", 2 ], [ "textbook_electronics", 3 ] ],
     "tools": [
@@ -78,7 +78,7 @@
     "proficiencies": [
       { "proficiency": "prof_elec_circuits", "required": true },
       { "proficiency": "prof_elec_semiconductors", "required": true },
-      { "proficiency": "prof_elec_integrated_circuits", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_elec_integrated_circuits", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "book_learn": [ [ "advanced_electronics", 4 ], [ "textbook_electronics", 4 ], [ "ic_reference_electronics", 3 ] ],
     "tools": [
diff --git a/data/json/recipes/practice/fabrication.json b/data/json/recipes/practice/fabrication.json
index 5c694c36610fe..82830278f3e96 100644
--- a/data/json/recipes/practice/fabrication.json
+++ b/data/json/recipes/practice/fabrication.json
@@ -10,7 +10,7 @@
     "skill_used": "fabrication",
     "skills_required": [ [ "archery", 1 ] ],
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
-    "proficiencies": [ { "proficiency": "prof_fletching", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_fletching", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "CUT", "level": 2 } ],
     "//": "Modifying so much the arrows/bolts will cause them to eventually lose their shape",
@@ -32,7 +32,7 @@
     "description": "Practice carving different forms and shapes in a piece of wood.",
     "skill_used": "fabrication",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 2 },
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "CUT", "level": 2 } ],
     "//": "One could use other wooden items to practice carving, but the stick and plank are the most easily acquired.",
@@ -50,7 +50,7 @@
     "description": "Practice basic carpentry by cutting, shaping and uniting some planks or sticks with nails.",
     "skill_used": "fabrication",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 2 },
-    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "HAMMER", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "//": "You destroy the wood with your practice, and the nails are now unusable.",
@@ -69,8 +69,8 @@
     "skill_used": "fabrication",
     "practice_data": { "min_difficulty": 2, "max_difficulty": 3, "skill_limit": 4 },
     "proficiencies": [
-      { "proficiency": "prof_metalworking", "fail_multiplier": 1, "time_multiplier": 1 },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_metalworking", "time_multiplier": 1, "skill_penalty": 0 },
+      { "proficiency": "prof_welding_basic", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "components": [ [ [ "sheet_metal_small", 24 ] ] ],
@@ -92,7 +92,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking", "required": true },
       { "proficiency": "prof_welding_basic", "required": true },
-      { "proficiency": "prof_welding", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_welding", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "components": [ [ [ "sheet_metal_small", 30 ] ] ],
diff --git a/data/json/recipes/practice/health.json b/data/json/recipes/practice/health.json
index 4ad9ef1b328f4..1173ffa8fee4a 100644
--- a/data/json/recipes/practice/health.json
+++ b/data/json/recipes/practice/health.json
@@ -10,7 +10,7 @@
     "skill_used": "firstaid",
     "time": "1 h",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 1 },
-    "proficiencies": [ { "proficiency": "prof_wound_care", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_wound_care", "time_multiplier": 1, "skill_penalty": 0 } ],
     "autolearn": [ [ "firstaid", 0 ] ],
     "flags": [ "BLIND_HARD" ],
     "tools": [
@@ -35,7 +35,7 @@
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "proficiencies": [
       { "proficiency": "prof_wound_care", "required": true },
-      { "proficiency": "prof_wound_care_expert", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_wound_care_expert", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "autolearn": [ [ "firstaid", 1 ] ],
     "flags": [ "BLIND_HARD" ],
diff --git a/data/json/recipes/practice/mechanics.json b/data/json/recipes/practice/mechanics.json
index 2bf8085de179d..051f1fcaa4fca 100644
--- a/data/json/recipes/practice/mechanics.json
+++ b/data/json/recipes/practice/mechanics.json
@@ -9,7 +9,7 @@
     "description": "Practice basic mechanics by using a pre-Cataclysm edutainment set.  Learn about hydraulics.",
     "skill_used": "mechanics",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 1, "skill_limit": 2 },
-    "proficiencies": [ { "proficiency": "prof_plumbing", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_plumbing", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 2 } ],
     "//": "You drain the battery charge but the kit can be reused.",
@@ -26,7 +26,7 @@
     "description": "Practice basic mechanics by using a pre-Cataclysm edutainment set.  Learn about robots.",
     "skill_used": "mechanics",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 1 },
-    "proficiencies": [ { "proficiency": "prof_elec_circuits", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_elec_circuits", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 2 } ],
     "//": "You drain the battery charge but the kit can be reused.",
@@ -43,7 +43,7 @@
     "description": "Practice basic mechanics by using a pre-Cataclysm edutainment set.  Learn about engines.",
     "skill_used": "mechanics",
     "practice_data": { "min_difficulty": 2, "max_difficulty": 2, "skill_limit": 3 },
-    "proficiencies": [ { "proficiency": "prof_basic_engines", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_basic_engines", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 2 } ],
     "//": "You drain the battery charge but the kit can be reused.",
diff --git a/data/json/recipes/practice/ranged.json b/data/json/recipes/practice/ranged.json
index bf6d5fef934e0..f1c0561b87c82 100644
--- a/data/json/recipes/practice/ranged.json
+++ b/data/json/recipes/practice/ranged.json
@@ -90,7 +90,7 @@
     "skill_used": "archery",
     "time": "30 m",
     "practice_data": { "min_difficulty": 2, "max_difficulty": 4, "skill_limit": 5 },
-    "proficiencies": [ { "proficiency": "prof_bow_basic", "fail_multiplier": 1, "time_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_bow_basic", "time_multiplier": 1.5, "skill_penalty": 0 } ],
     "autolearn": [ [ "archery", 3 ] ],
     "book_learn": [ [ "book_archery", 2 ], [ "manual_archery", 2 ] ],
     "tools": [
@@ -143,7 +143,7 @@
     "practice_data": { "min_difficulty": 2, "max_difficulty": 3, "skill_limit": 3 },
     "proficiencies": [
       { "proficiency": "prof_bow_basic", "required": true },
-      { "proficiency": "prof_bow_expert", "fail_multiplier": 1, "time_multiplier": 2 }
+      { "proficiency": "prof_bow_expert", "time_multiplier": 2, "skill_penalty": 0 }
     ],
     "autolearn": [ [ "archery", 3 ] ],
     "flags": [ "BLIND_EASY" ],
diff --git a/data/json/recipes/practice/survival.json b/data/json/recipes/practice/survival.json
index 253e310e40be5..fe3bd4686bd0b 100644
--- a/data/json/recipes/practice/survival.json
+++ b/data/json/recipes/practice/survival.json
@@ -10,7 +10,7 @@
     "skill_used": "survival",
     "skills_required": [ [ "fabrication", 1 ] ],
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 2 },
-    "proficiencies": [ { "proficiency": "prof_knapping", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_knapping", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "qualities": [ { "id": "HAMMER", "level": 1 }, { "id": "HAMMER_SOFT", "level": 1 } ],
     "//": "You destroy the rocks with your practice, leaving you with some pebbles.",
@@ -32,7 +32,7 @@
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "proficiencies": [
       { "proficiency": "prof_knapping", "required": true },
-      { "proficiency": "prof_knapping_speed", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_knapping_speed", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "qualities": [
diff --git a/data/json/recipes/practice/tailoring.json b/data/json/recipes/practice/tailoring.json
index 6cd46f2296933..7b4e4ab62e49c 100644
--- a/data/json/recipes/practice/tailoring.json
+++ b/data/json/recipes/practice/tailoring.json
@@ -9,8 +9,8 @@
     "description": "Practice knitting whatever comes to your mind, from simple forms to elaborate and rich designs.",
     "skill_used": "tailor",
     "proficiencies": [
-      { "proficiency": "prof_knitting", "fail_multiplier": 1, "time_multiplier": 1 },
-      { "proficiency": "prof_knitting_speed", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_knitting", "time_multiplier": 1, "skill_penalty": 0 },
+      { "proficiency": "prof_knitting_speed", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 2 },
@@ -27,7 +27,7 @@
     "name": "garment closures",
     "description": "Practice the principles of garment closures by sewing some buttons and similar fasteners to some cotton patches.",
     "skill_used": "tailor",
-    "proficiencies": [ { "proficiency": "prof_closures", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_closures", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "autolearn": [ [ "tailor", 2 ] ],
@@ -44,7 +44,7 @@
     "name": "fabric waterproofing",
     "description": "Practice the principles of sealing garments and fabric against water by making a basic waterproof layer from plastic bags duct taped together, you will need some water and a rag.",
     "skill_used": "tailor",
-    "proficiencies": [ { "proficiency": "prof_closures_waterproofing", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_closures_waterproofing", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "autolearn": [ [ "tailor", 2 ] ],
@@ -62,7 +62,7 @@
     "name": "advanced polymer sewing",
     "description": "Practice cutting and sewing together advanced polymers like Kevlar or Nomex.",
     "skill_used": "tailor",
-    "proficiencies": [ { "proficiency": "prof_polymerworking", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_polymerworking", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "autolearn": [ [ "tailor", 2 ] ],
@@ -81,7 +81,7 @@
     "name": "stretch fabric",
     "description": "Practice the use of stretch fabric in clothing by making and modifying some basic garment forms with lycra patches.",
     "skill_used": "tailor",
-    "proficiencies": [ { "proficiency": "prof_elastics", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_elastics", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "autolearn": [ [ "tailor", 2 ] ],
@@ -98,7 +98,7 @@
     "name": "leatherworking (beginner)",
     "description": "Practice basic leatherworking skills by cutting and punching holes in leather, and stitching together leather patches.",
     "skill_used": "tailor",
-    "proficiencies": [ { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 1, "max_difficulty": 2, "skill_limit": 3 },
     "autolearn": [ [ "tailor", 2 ] ],
@@ -116,7 +116,7 @@
     "skill_used": "tailor",
     "proficiencies": [
       { "proficiency": "prof_leatherworking_basic", "required": true },
-      { "proficiency": "prof_leatherworking", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_leatherworking", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 2, "max_difficulty": 3, "skill_limit": 4 },
@@ -138,7 +138,7 @@
     "skills_required": [ [ "fabrication", 3 ] ],
     "proficiencies": [
       { "proficiency": "prof_leatherworking_basic", "required": true },
-      { "proficiency": "prof_chitinworking", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_chitinworking", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 3, "max_difficulty": 4, "skill_limit": 5 },
@@ -157,7 +157,7 @@
     "name": "joint articulation",
     "description": "Practice the making of articulated joints in clothing by sewing some gloves and other basic cloth joints with several layers of cotton patches for rigidity.",
     "skill_used": "tailor",
-    "proficiencies": [ { "proficiency": "prof_articulation", "fail_multiplier": 1, "time_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_articulation", "time_multiplier": 1, "skill_penalty": 0 } ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 3, "max_difficulty": 4, "skill_limit": 5 },
     "autolearn": [ [ "tailor", 4 ] ],
diff --git a/data/json/recipes/recipe_food.json b/data/json/recipes/recipe_food.json
index 5c635987a3e46..ee2ddfd617c84 100644
--- a/data/json/recipes/recipe_food.json
+++ b/data/json/recipes/recipe_food.json
@@ -41,7 +41,7 @@
       { "proficiency": "prof_food_prep" },
       { "proficiency": "prof_frying" },
       { "proficiency": "prof_frying_bread" },
-      { "proficiency": "prof_baking", "fail_multiplier": 1.1 }
+      { "proficiency": "prof_baking", "skill_penalty": 0.1 }
     ],
     "components": [
       [ [ "flour_any", 10, "LIST" ] ],
diff --git a/data/json/recipes/recipe_others.json b/data/json/recipes/recipe_others.json
index fd32a6001a9bf..de1b51b4ffe16 100644
--- a/data/json/recipes/recipe_others.json
+++ b/data/json/recipes/recipe_others.json
@@ -260,7 +260,7 @@
     "using": [ [ "welding_standard", 5 ], [ "steel_standard", 2 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [
@@ -291,7 +291,7 @@
     "using": [ [ "welding_standard", 10 ], [ "steel_standard", 4 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [
@@ -525,7 +525,7 @@
     "autolearn": true,
     "qualities": [ { "id": "SEW", "level": 1 }, { "id": "LEATHER_AWL", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "skill_penalty": 0.5 },
       { "proficiency": "prof_leatherworking" },
       { "proficiency": "prof_closures", "required": false, "time_multiplier": 1.5 },
       { "proficiency": "prof_closures_waterproofing" }
@@ -549,7 +549,7 @@
     "autolearn": true,
     "qualities": [ { "id": "SEW", "level": 1 }, { "id": "LEATHER_AWL", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "skill_penalty": 0.5 },
       { "proficiency": "prof_leatherworking" },
       { "proficiency": "prof_closures", "required": false, "time_multiplier": 1.5 },
       { "proficiency": "prof_closures_waterproofing" }
@@ -576,7 +576,7 @@
     "autolearn": true,
     "qualities": [ { "id": "SEW", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "skill_penalty": 0.5 },
       { "proficiency": "prof_furriery" }
     ],
     "components": [ [ [ "fur", 24 ], [ "tanned_pelt", 4 ], [ "sheet_fur_patchwork", 4 ] ], [ [ "filament", 20, "LIST" ] ] ]
@@ -612,7 +612,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "pipe", 8 ] ], [ [ "sheet_metal", 2 ] ], [ [ "sheet_metal_small", 4 ] ], [ [ "pipe_fittings", 4 ] ] ]
@@ -847,7 +847,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ],
     "tools": [ [ [ "swage", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -120 ], [ "water_clean", -120 ] ] ],
     "components": [ [ [ "steel_lump", 1 ], [ "steel_chunk", 4 ], [ "scrap", 20 ] ] ]
@@ -868,7 +868,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ],
     "tools": [
       [ [ "tongs", -1 ] ],
@@ -1428,7 +1428,7 @@
     "using": [ [ "welding_standard", 15 ], [ "steel_standard", 6 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [
@@ -1455,7 +1455,7 @@
     "using": [ [ "welding_standard", 15 ], [ "steel_standard", 6 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [
@@ -1489,7 +1489,7 @@
     "using": [ [ "soldering_standard", 25 ], [ "welding_standard", 20 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [
@@ -1970,7 +1970,7 @@
     "using": [ [ "welding_standard", 3 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
diff --git a/data/json/recipes/recipe_vehicle.json b/data/json/recipes/recipe_vehicle.json
index 88066a7b7a8d4..bc5305da10cc5 100644
--- a/data/json/recipes/recipe_vehicle.json
+++ b/data/json/recipes/recipe_vehicle.json
@@ -695,7 +695,7 @@
       { "id": "CUT", "level": 2 },
       { "id": "CHISEL_WOOD", "level": 1 }
     ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "skill_penalty": 0 } ],
     "components": [
       [ [ "stick", 1 ], [ "2x4", 1 ] ],
       [ [ "log", 1 ] ],
@@ -1326,7 +1326,7 @@
     "using": [ [ "welding_standard", 6 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "material_aluminium_ingot", 3 ], [ "scrap_aluminum", 34 ] ] ]
diff --git a/data/json/recipes/tools/containers.json b/data/json/recipes/tools/containers.json
index 8d5570a4903e5..ffbcab0af76d4 100644
--- a/data/json/recipes/tools/containers.json
+++ b/data/json/recipes/tools/containers.json
@@ -72,7 +72,7 @@
     "using": [ [ "welding_standard", 2 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 } ],
@@ -119,7 +119,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 } ],
@@ -312,7 +312,7 @@
     "using": [ [ "welding_standard", 15 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "sheet_metal", 4 ], [ "sheet_metal_small", 80 ] ] ]
@@ -331,7 +331,7 @@
     "using": [ [ "welding_standard", 10 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "components": [ [ [ "sheet_metal", 2 ], [ "sheet_metal_small", 32 ] ] ]
@@ -565,7 +565,7 @@
     "using": [ [ "welding_standard", 3 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
@@ -708,7 +708,7 @@
     "using": [ [ "welding_standard", 30 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 3 }, { "id": "SAW_M", "level": 1 } ],
diff --git a/data/json/recipes/tools/tool.json b/data/json/recipes/tools/tool.json
index 0a44b1f9899df..d31f698557e19 100644
--- a/data/json/recipes/tools/tool.json
+++ b/data/json/recipes/tools/tool.json
@@ -62,7 +62,7 @@
     "using": [ [ "welding_standard", 10 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
@@ -89,7 +89,7 @@
     "using": [ [ "welding_standard", 10 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
@@ -144,7 +144,7 @@
     "using": [ [ "welding_standard", 10 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 3 }, { "id": "SCREW", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
@@ -278,8 +278,8 @@
         "proficiency": "prof_lockpicking",
         "required": false,
         "time_multiplier": 2,
-        "fail_multiplier": 1.5,
-        "learning_time_multiplier": 0
+        "learning_time_multiplier": 0,
+        "skill_penalty": 0.5
       }
     ],
     "qualities": [ [ { "id": "HAMMER_FINE", "level": 1 }, { "id": "WRENCH", "level": 1 } ], { "id": "SAW_M", "level": 1 } ],
@@ -300,8 +300,8 @@
         "proficiency": "prof_lockpicking",
         "required": false,
         "time_multiplier": 2,
-        "fail_multiplier": 1.5,
-        "learning_time_multiplier": 0
+        "learning_time_multiplier": 0,
+        "skill_penalty": 0.5
       }
     ],
     "qualities": [ [ { "id": "HAMMER_FINE", "level": 1 }, { "id": "WRENCH", "level": 1 } ] ],
@@ -321,8 +321,8 @@
         "proficiency": "prof_lockpicking",
         "required": false,
         "time_multiplier": 2,
-        "fail_multiplier": 1.5,
-        "learning_time_multiplier": 0
+        "learning_time_multiplier": 0,
+        "skill_penalty": 0.5
       }
     ],
     "//": "First item in the components list is serving as a torsion wrench. Many small flat items can be jammed in and turned to apply torsion.  Second item in the list is the pick itself which has to be a small, bent bit of wire or pin.",
@@ -1406,7 +1406,7 @@
     "proficiencies": [
       { "proficiency": "prof_elec_soldering" },
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [
diff --git a/data/json/recipes/tools/tools_electronic.json b/data/json/recipes/tools/tools_electronic.json
index 8adff8d2eb135..d60f0754dd935 100644
--- a/data/json/recipes/tools/tools_electronic.json
+++ b/data/json/recipes/tools/tools_electronic.json
@@ -31,8 +31,8 @@
       {
         "proficiency": "prof_welding",
         "time_multiplier": 1.1,
-        "fail_multiplier": 1.1,
-        "learning_time_multiplier": 0.25
+        "learning_time_multiplier": 0.25,
+        "skill_penalty": 0.1
       }
     ],
     "qualities": [ { "id": "SCREW", "level": 1 }, { "id": "SAW_M", "level": 1 } ],
@@ -409,7 +409,7 @@
     "autolearn": [ [ "electronics", 2 ] ],
     "book_learn": [ [ "manual_electronics", 1 ], [ "advanced_electronics", 2 ], [ "textbook_anarch", 2 ] ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "SCREW", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_elec_soldering", "fail_multiplier": 1.125 }, { "proficiency": "prof_elec_circuits" } ],
+    "proficiencies": [ { "proficiency": "prof_elec_soldering", "skill_penalty": 0.125 }, { "proficiency": "prof_elec_circuits" } ],
     "components": [
       [ [ "e_scrap", 2 ], [ "glowplug", 1 ] ],
       [ [ "copper", 1 ], [ "nail", 1 ], [ "wire", 1 ] ],
diff --git a/data/json/recipes/tools/tools_hand.json b/data/json/recipes/tools/tools_hand.json
index 4821a95ab4007..be9887337359c 100644
--- a/data/json/recipes/tools/tools_hand.json
+++ b/data/json/recipes/tools/tools_hand.json
@@ -1082,7 +1082,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 2 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
diff --git a/data/json/recipes/tools/tools_primitive.json b/data/json/recipes/tools/tools_primitive.json
index 801fc54a4464e..5320824b19a8d 100644
--- a/data/json/recipes/tools/tools_primitive.json
+++ b/data/json/recipes/tools/tools_primitive.json
@@ -54,7 +54,7 @@
     "time": "20 m",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "skill_penalty": 0 } ],
     "components": [ [ [ "stick", 1 ], [ "2x4", 1 ] ] ]
   },
   {
@@ -73,7 +73,7 @@
       { "id": "CUT", "level": 2 },
       { "id": "CHISEL_WOOD", "level": 1 }
     ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "skill_penalty": 0 } ],
     "components": [
       [ [ "stick", 1 ], [ "2x4", 1 ] ],
       [ [ "2x4", 1 ] ],
@@ -97,7 +97,7 @@
       { "id": "CUT", "level": 2 },
       { "id": "CHISEL_WOOD", "level": 1 }
     ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 3, "skill_penalty": 0 } ],
     "components": [
       [ [ "stick", 1 ], [ "2x4", 1 ] ],
       [ [ "log", 1 ] ],
diff --git a/data/json/recipes/weapon/bashing.json b/data/json/recipes/weapon/bashing.json
index 0fca0c144b15f..ed8eb559e082f 100644
--- a/data/json/recipes/weapon/bashing.json
+++ b/data/json/recipes/weapon/bashing.json
@@ -89,7 +89,7 @@
     "reversible": true,
     "book_learn": [ [ "textbook_electronics", 3 ], [ "advanced_electronics", 3 ], [ "recipe_melee", 4 ] ],
     "using": [ [ "soldering_standard", 10 ] ],
-    "proficiencies": [ { "proficiency": "prof_elec_soldering", "fail_multiplier": 1.5 }, { "proficiency": "prof_shock_weapons" } ],
+    "proficiencies": [ { "proficiency": "prof_elec_soldering", "skill_penalty": 0.5 }, { "proficiency": "prof_shock_weapons" } ],
     "qualities": [ { "id": "SCREW", "level": 1 } ],
     "components": [ [ [ "i_staff", 1 ] ], [ [ "tazer", 1 ] ], [ [ "cable", 10 ] ] ]
   },
@@ -105,7 +105,7 @@
     "time": "3 h",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 } ],
-    "proficiencies": [ { "proficiency": "prof_carving" }, { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving" }, { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ], [ "stick_long", 1 ] ], [ [ "leather", 5 ] ] ]
   },
   {
@@ -124,8 +124,8 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_toolsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 }
     ],
     "tools": [ [ [ "swage", -1 ] ] ],
     "components": [ [ [ "stick_long", 1 ] ], [ [ "fur", 2 ], [ "leather", 2 ] ] ]
@@ -162,7 +162,7 @@
     "time": "45 m",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ], [ "pool_cue", 1 ] ] ]
   },
   {
@@ -199,7 +199,7 @@
     "time": "5 m",
     "autolearn": true,
     "qualities": [ { "id": "HAMMER", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ] ], [ [ "nail", 6 ] ] ]
   },
   {
@@ -225,7 +225,7 @@
     "time": "10 m",
     "autolearn": true,
     "qualities": [ { "id": "HAMMER", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 } ],
     "components": [ [ [ "bat", 1 ] ], [ [ "nail", 6 ] ] ]
   },
   {
@@ -250,10 +250,7 @@
     "time": "25 m",
     "autolearn": true,
     "qualities": [ { "id": "SAW_W", "level": 1 } ],
-    "proficiencies": [
-      { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 }, { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ] ] ]
   },
   {
@@ -266,10 +263,7 @@
     "time": "25 m",
     "autolearn": true,
     "qualities": [ { "id": "SAW_W", "level": 1 } ],
-    "proficiencies": [
-      { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 }, { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ] ] ]
   },
   {
@@ -283,7 +277,7 @@
     "time": "15 m",
     "autolearn": true,
     "qualities": [ { "id": "HAMMER", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 } ],
     "components": [ [ [ "sword_wood", 1 ] ], [ [ "nail", 12 ] ] ]
   },
   {
@@ -409,10 +403,7 @@
     "reversible": true,
     "autolearn": true,
     "using": [ [ "cordage", 4 ] ],
-    "proficiencies": [
-      { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 }, { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "qualities": [ { "id": "HAMMER", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "components": [ [ [ "nail", 16 ] ], [ [ "stick", 1 ], [ "2x4", 1 ] ] ]
   },
@@ -446,7 +437,7 @@
     "time": "30 m",
     "book_learn": [ [ "recipe_melee", 1 ], [ "textbook_weapeast", 7 ] ],
     "using": [ [ "sewing_standard", 5 ] ],
-    "proficiencies": [ { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 } ],
     "qualities": [ { "id": "HAMMER", "level": 1 }, { "id": "SAW_M", "level": 1 } ],
     "components": [ [ [ "leather", 4 ] ], [ [ "scrap", 8 ] ] ]
   },
@@ -492,7 +483,7 @@
     "difficulty": 6,
     "time": "1 h",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_plasticworking", "fail_multiplier": 5 } ],
+    "proficiencies": [ { "proficiency": "prof_plasticworking", "skill_penalty": 4 } ],
     "tools": [ [ [ "surface_heat", 10, "LIST" ] ] ],
     "using": [ [ "plastic_molding", 1 ] ],
     "components": [ [ [ "plastic_chunk", 10 ] ] ]
@@ -526,9 +517,9 @@
     "using": [ [ "soldering_standard", 10 ], [ "surface_heat", 10 ], [ "plastic_molding", 1 ] ],
     "qualities": [ { "id": "SCREW", "level": 1 } ],
     "proficiencies": [
-      { "proficiency": "prof_elec_soldering", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_elec_soldering", "skill_penalty": 0.5 },
       { "proficiency": "prof_shock_weapons" },
-      { "proficiency": "prof_plasticworking", "fail_multiplier": 1.5 }
+      { "proficiency": "prof_plasticworking", "skill_penalty": 0.5 }
     ],
     "components": [
       [ [ "plastic_chunk", 10 ] ],
@@ -552,7 +543,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_toolsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -571,7 +562,7 @@
     "time": "5 h 40 m",
     "book_learn": [ [ "textbook_weapeast", 2 ] ],
     "qualities": [ { "id": "SAW_W", "level": 1 }, { "id": "CUT", "level": 2 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0.5 } ],
     "//": "Bokken is a single piece of wood, and the stout branch just isn't large enough.",
     "components": [
       [ [ "stick_long", 1 ] ],
@@ -601,8 +592,8 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_toolsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "components": [ [ [ "2x4", 3 ], [ "stick", 6 ] ], [ [ "fur", 3 ], [ "leather", 3 ] ] ]
@@ -617,7 +608,7 @@
     "time": "15 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "components": [
       [ [ "stick", 1 ] ],
       [ [ "steel_chunk", 1 ], [ "steel_lump", 1 ], [ "pipe_fittings", 1 ] ],
@@ -637,7 +628,7 @@
     "reversible": true,
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "components": [
       [ [ "stick", 1 ] ],
       [ [ "steel_lump", 1 ], [ "steel_chunk", 1 ], [ "pipe_fittings", 1 ] ],
@@ -696,7 +687,7 @@
     "time": "30 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
     "components": [ [ [ "mace_simple", 1 ] ], [ [ "nail", 2 ] ], [ [ "cordage", 1, "LIST" ], [ "duct_tape", 50 ] ] ]
   },
@@ -713,7 +704,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "forging_standard", 1 ], [ "bronzesmithing_tools", 1 ] ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
@@ -735,8 +726,8 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_toolsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 },
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "swage", -1 ] ] ],
@@ -770,7 +761,7 @@
     "//1": "TODO: adjust crafting time down by 4 hours when it's possible to separate the oiling time from the crafting time easily.",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "CUT_FINE", "level": 1 }, { "id": "FILE", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1.5, "max_experience": "60 m" } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "max_experience": "60 m", "skill_penalty": 0.5 } ],
     "//2": "Max experience set because waiting for oil to soak in isn't really teaching you anything.  Remove this when crafting time reduced to only carving time.",
     "components": [
       [ [ "stick_long", 1 ] ],
@@ -797,7 +788,7 @@
     "//1": "TODO: adjust crafting time down by 4 hours (240 minutes) when it's possible to separate the oiling time from the crafting time easily.",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "CUT_FINE", "level": 1 }, { "id": "FILE", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1.2, "max_experience": "30 m" } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "max_experience": "30 m", "skill_penalty": 0.2 } ],
     "//2": "Max experience set because waiting for oil to soak in isn't really teaching you anything.  Remove this when crafting time reduced to only carving time.",
     "components": [
       [ [ "q_staff", 1 ] ],
diff --git a/data/json/recipes/weapon/cutting.json b/data/json/recipes/weapon/cutting.json
index 67dba57d2dd58..d4598e0482d87 100644
--- a/data/json/recipes/weapon/cutting.json
+++ b/data/json/recipes/weapon/cutting.json
@@ -230,7 +230,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -248,7 +248,7 @@
     "time": "15 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 } ],
     "components": [
       [ [ "duct_tape", 100 ] ],
       [ [ "blade", 1 ], [ "knife_meat_cleaver", 1 ], [ "knife_vegetable_cleaver", 1 ] ],
@@ -267,7 +267,7 @@
     "reversible": true,
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.5 } ],
     "components": [
       [ [ "duct_tape", 100 ] ],
       [ [ "blade", 1 ], [ "knife_meat_cleaver", 1 ], [ "knife_vegetable_cleaver", 1 ] ],
@@ -288,7 +288,7 @@
     "decomp_learn": 1,
     "autolearn": true,
     "qualities": [ { "id": "HAMMER", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 } ],
     "components": [ [ [ "duct_tape", 50 ] ], [ [ "blade_scythe", 1 ] ], [ [ "stick_long", 1 ] ] ]
   },
   {
@@ -306,7 +306,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 24 ], [ "steel_standard", 6 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -371,8 +371,8 @@
       {
         "proficiency": "prof_plasticworking",
         "time_multiplier": 1.1,
-        "fail_multiplier": 1,
-        "learning_time_multiplier": 0.1
+        "learning_time_multiplier": 0.1,
+        "skill_penalty": 0
       },
       { "proficiency": "prof_bladesmith" }
     ],
@@ -413,8 +413,8 @@
       {
         "proficiency": "prof_plasticworking",
         "time_multiplier": 1.1,
-        "fail_multiplier": 1,
-        "learning_time_multiplier": 0.1
+        "learning_time_multiplier": 0.1,
+        "skill_penalty": 0
       },
       { "proficiency": "prof_bladesmith" }
     ],
@@ -437,7 +437,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 20 ], [ "steel_standard", 5 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -498,7 +498,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -634,7 +634,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "mc_steel_standard", 3 ] ],
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "GRIND", "level": 2 } ],
@@ -655,7 +655,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "hc_steel_standard", 3 ] ],
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "GRIND", "level": 2 } ],
@@ -677,7 +677,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
       { "proficiency": "prof_case_hardening" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "lc_steel_standard", 3 ], [ "carbon", 1 ] ],
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "GRIND", "level": 2 } ],
@@ -699,7 +699,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
       { "proficiency": "prof_quenching" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0.15 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "mc_steel_standard", 3 ] ],
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "GRIND", "level": 2 } ],
@@ -853,7 +853,7 @@
     "autolearn": true,
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "skill_penalty": 0 }
     ],
     "components": [ [ [ "sheet_metal", 1 ] ], [ [ "nuts_bolts", 4 ] ], [ [ "2x4", 1 ], [ "stick", 1 ] ] ],
     "tools": [ [ [ "angle_grinder", 50 ] ] ],
@@ -872,7 +872,7 @@
     "autolearn": true,
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1 },
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "skill_penalty": 0 },
       { "proficiency": "prof_welding_basic" },
       { "proficiency": "prof_welding" }
     ],
@@ -895,7 +895,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
@@ -916,7 +916,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 18 ], [ "steel_standard", 6 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
@@ -937,7 +937,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
@@ -958,7 +958,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -2042,7 +2042,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 12 ], [ "steel_standard", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -2063,7 +2063,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -2084,7 +2084,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -2107,7 +2107,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "hotcut", -1 ] ] ],
@@ -2149,7 +2149,7 @@
     "using": [ [ "soldering_standard", 20 ], [ "blacksmithing_standard", 10 ] ],
     "qualities": [ { "id": "HAMMER", "level": 3 }, { "id": "SAW_M", "level": 1 }, { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "swage", -1 ] ], [ [ "metal_tank", -1 ] ], [ [ "water", -80 ], [ "water_clean", -80 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_metalworking" }, { "proficiency": "prof_quenching", "fail_multiplier": 2 } ],
+    "proficiencies": [ { "proficiency": "prof_metalworking" }, { "proficiency": "prof_quenching", "skill_penalty": 1 } ],
     "components": [
       [ [ "machete", 1 ] ],
       [ [ "duct_tape", 150 ] ],
diff --git a/data/json/recipes/weapon/piercing.json b/data/json/recipes/weapon/piercing.json
index 65fd1ae69a1cb..6f39bd64ec5e8 100644
--- a/data/json/recipes/weapon/piercing.json
+++ b/data/json/recipes/weapon/piercing.json
@@ -15,7 +15,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "hotcut", -1 ] ] ],
@@ -56,7 +56,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "hotcut", -1 ] ] ],
@@ -78,7 +78,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "hotcut", -1 ] ] ],
@@ -117,7 +117,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 2 ], [ "steel_tiny", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -139,7 +139,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_toolsmithing" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "hotcut", -1 ] ] ],
@@ -159,7 +159,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 3 ], [ "steel_tiny", 3 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -181,7 +181,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "ANVIL", "level": 3 }, { "id": "HAMMER", "level": 3 }, { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "tongs", -1 ] ] ],
@@ -207,7 +207,7 @@
     "proficiencies": [
       { "proficiency": "prof_knapping" },
       { "proficiency": "prof_knapping_speed" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "skill_penalty": 0.15 }
     ],
     "components": [ [ [ "spear_shaft", 1 ] ], [ [ "rock_flaking_any", 1, "LIST" ] ], [ [ "cordage_short", 1, "LIST" ] ] ]
   },
@@ -231,7 +231,7 @@
     "proficiencies": [
       { "proficiency": "prof_knapping" },
       { "proficiency": "prof_knapping_speed" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "skill_penalty": 0.15 }
     ],
     "components": [ [ [ "stick_long", 1 ] ], [ [ "rock_flaking_any", 1, "LIST" ] ], [ [ "cordage_short", 1, "LIST" ] ] ]
   },
@@ -308,7 +308,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "forging_standard", 2 ], [ "bronzesmithing_tools", 1 ] ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
@@ -332,7 +332,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "forging_standard", 1 ], [ "bronzesmithing_tools", 1 ] ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
@@ -352,7 +352,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "forging_standard", 1 ], [ "bronzesmithing_tools", 1 ] ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
@@ -373,7 +373,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -413,7 +413,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 4 ], [ "steel_standard", 1 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
@@ -514,7 +514,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1 }
+      { "proficiency": "prof_leatherworking_basic", "skill_penalty": 0 }
     ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
     "tools": [ [ [ "hotcut", -1 ] ] ],
@@ -597,7 +597,7 @@
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 } ],
     "tools": [ [ [ "fire", -1 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [
       [ [ "long_pole", 1 ] ],
       [ [ "cotton_patchwork", 1 ], [ "felt_patch", 1 ], [ "leather", 1 ], [ "fur", 1 ] ],
@@ -620,7 +620,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "components": [
       [ [ "long_pole", 1 ] ],
@@ -642,7 +642,7 @@
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 } ],
     "tools": [ [ [ "fire", -1 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "stick_long", 1 ], [ "pointy_stick_long", 1 ] ] ]
   },
   {
@@ -656,7 +656,7 @@
     "time": "120 m",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "stick_long", 1 ], [ "pointy_stick_long", 1 ] ] ]
   },
   {
@@ -670,7 +670,7 @@
     "time": "60 m",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "spear_shaft", 1 ] ] ]
   },
   {
@@ -689,7 +689,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "components": [ [ [ "spear_shaft", 1 ] ], [ [ "copper_scrap_equivalent", 2, "LIST" ] ] ]
   },
@@ -795,7 +795,7 @@
     "time": "2 h",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "components": [
       [ [ "stick_long", 1 ] ],
       [
@@ -820,7 +820,7 @@
     "time": "30 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
     "components": [
       [ [ "spear_shaft", 1 ] ],
@@ -846,7 +846,7 @@
     "time": "2 h",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "components": [
       [ [ "stick_long", 1 ], [ "long_pole", 1 ] ],
       [
@@ -878,7 +878,7 @@
     "reversible": true,
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "components": [
       [ [ "stick_long", 1 ], [ "long_pole", 1 ] ],
       [
@@ -910,7 +910,7 @@
     "time": "30 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
     "components": [ [ [ "spear_knife", 1 ] ], [ [ "nail", 2 ], [ "nuts_bolts", 2 ] ], [ [ "cordage", 1, "LIST" ], [ "duct_tape", 50 ] ] ]
   },
@@ -925,7 +925,7 @@
     "time": "30 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 } ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "HAMMER", "level": 1 }, { "id": "DRILL", "level": 1 } ],
     "components": [
       [ [ "spear_shaft", 1 ] ],
@@ -1016,8 +1016,8 @@
       {
         "proficiency": "prof_plasticworking",
         "time_multiplier": 1.1,
-        "fail_multiplier": 1,
-        "learning_time_multiplier": 0.1
+        "learning_time_multiplier": 0.1,
+        "skill_penalty": 0
       }
     ],
     "using": [ [ "blacksmithing_standard", 3 ], [ "steel_tiny", 3 ] ],
diff --git a/data/json/recipes/weapon/ranged.json b/data/json/recipes/weapon/ranged.json
index cfcf35dc3b394..2d791ded5f218 100644
--- a/data/json/recipes/weapon/ranged.json
+++ b/data/json/recipes/weapon/ranged.json
@@ -127,7 +127,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "swage", -1 ] ] ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 1 ] ], [ [ "hc_steel_chunk", 1 ] ], [ [ "flint", 1 ] ] ]
@@ -156,7 +156,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ] ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 1 ] ], [ [ "hc_steel_chunk", 1 ] ], [ [ "flint", 1 ] ] ]
@@ -185,7 +185,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ] ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 1 ] ], [ [ "hc_steel_chunk", 1 ] ], [ [ "flint", 1 ] ] ]
@@ -214,7 +214,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ] ],
     "components": [ [ [ "2x4", 1 ] ], [ [ "pipe", 1 ] ], [ [ "hc_steel_chunk", 1 ] ], [ [ "flint", 1 ] ] ]
@@ -237,7 +237,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 2 ] ], [ [ "hc_steel_chunk", 2 ] ], [ [ "flint", 2 ] ] ]
   },
@@ -272,7 +272,7 @@
     "proficiencies": [
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_spring" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 }, { "id": "SCREW", "level": 1 } ],
     "components": [ [ [ "2x4", 2 ], [ "stick", 2 ] ], [ [ "hose", 4 ] ], [ [ "scrap", 4 ] ] ]
@@ -291,7 +291,7 @@
     "proficiencies": [
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_spring" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 }, { "id": "SCREW", "level": 1 } ],
     "components": [ [ [ "2x4", 3 ], [ "stick", 3 ] ], [ [ "hose", 8 ] ], [ [ "scrap", 6 ] ] ]
@@ -310,7 +310,7 @@
     "proficiencies": [
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_spring" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "qualities": [ { "id": "SAW_M", "level": 1 }, { "id": "SCREW", "level": 1 } ],
     "components": [ [ [ "2x4", 1 ], [ "stick", 1 ] ], [ [ "hose", 2 ] ], [ [ "scrap", 3 ] ] ]
@@ -557,7 +557,7 @@
     "time": "1 h",
     "autolearn": true,
     "qualities": [ { "id": "CUT", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 4, "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 4, "skill_penalty": 0.5 } ],
     "components": [ [ [ "stick", 1 ], [ "2x4", 1 ] ] ]
   },
   {
@@ -587,7 +587,7 @@
     "autolearn": true,
     "using": [ [ "sewing_standard", 40 ] ],
     "qualities": [ { "id": "CUT", "level": 2 } ],
-    "proficiencies": [ { "proficiency": "prof_fibers", "time_multiplier": 4, "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "time_multiplier": 4, "skill_penalty": 0 } ],
     "components": [ [ [ "cordage", 32, "LIST" ] ], [ [ "rock", 8 ] ] ]
   },
   {
@@ -618,7 +618,7 @@
     "time": "15 m",
     "reversible": true,
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_fibers", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_fibers", "skill_penalty": 0 } ],
     "using": [ [ "cordage", 3 ] ]
   },
   {
@@ -857,7 +857,7 @@
       { "id": "WRENCH", "level": 1 }
     ],
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" }
     ],
     "components": [
@@ -881,7 +881,7 @@
     "reversible": true,
     "decomp_learn": 2,
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" }
     ],
     "book_learn": [ [ "recipe_bows", 2 ], [ "manual_archery", 4 ], [ "book_archery", 3 ], [ "textbook_armschina", 5 ] ],
@@ -897,7 +897,7 @@
     "skill_used": "fabrication",
     "skills_required": [ [ "traps", 2 ], [ "archery", 2 ] ],
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" },
       { "proficiency": "prof_carving", "time_multiplier": 1.5 }
     ],
@@ -921,7 +921,7 @@
     "reversible": true,
     "decomp_learn": 2,
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" }
     ],
     "book_learn": [ [ "recipe_bows", 1 ], [ "manual_archery", 3 ], [ "book_archery", 2 ] ],
@@ -1223,7 +1223,7 @@
       { "id": "SAW_W", "level": 1 }
     ],
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" },
       { "proficiency": "prof_carving", "time_multiplier": 1.5 }
     ],
@@ -1250,7 +1250,7 @@
     "decomp_learn": 4,
     "book_learn": [ [ "recipe_bows", 4 ], [ "textbook_weapeast", 6 ] ],
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" },
       { "proficiency": "prof_carving", "time_multiplier": 1.5 }
     ],
diff --git a/data/mods/Aftershock/items/armor/exosuit/exosuit_recipes.json b/data/mods/Aftershock/items/armor/exosuit/exosuit_recipes.json
index 479b25d77b9e6..9ea180c82d2cf 100644
--- a/data/mods/Aftershock/items/armor/exosuit/exosuit_recipes.json
+++ b/data/mods/Aftershock/items/armor/exosuit/exosuit_recipes.json
@@ -17,7 +17,7 @@
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -38,7 +38,7 @@
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -59,7 +59,7 @@
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
@@ -80,7 +80,7 @@
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ]
   },
   {
diff --git a/data/mods/DinoMod/recipes/pets_bear.json b/data/mods/DinoMod/recipes/pets_bear.json
index dfa0b7f4e209e..3bfdc4836d3e3 100644
--- a/data/mods/DinoMod/recipes/pets_bear.json
+++ b/data/mods/DinoMod/recipes/pets_bear.json
@@ -53,7 +53,7 @@
     "proficiencies": [
       { "proficiency": "prof_chain_armour" },
       { "proficiency": "prof_closures" },
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 }
     ]
   },
   {
@@ -251,7 +251,7 @@
     "book_learn": [ [ "textbook_tailor", 5 ], [ "tailor_portfolio", 5 ], [ "textbook_armwest", 4 ], [ "textbook_armschina", 4 ] ],
     "using": [ [ "sewing_standard", 260 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -273,7 +273,7 @@
     "using": [ [ "forging_standard", 120 ], [ "bronzesmithing_tools", 10 ] ],
     "components": [ [ [ "scrap_bronze", 60 ] ], [ [ "leather_armor_bear", 1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_redsmithing" },
@@ -293,7 +293,7 @@
     "using": [ [ "blacksmithing_standard", 800 ], [ "steel_standard", 200 ], [ "fabric_leather_fur_hide", 30 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
diff --git a/data/mods/DinoMod/recipes/pets_elephant.json b/data/mods/DinoMod/recipes/pets_elephant.json
index 8e978092f8b03..98df6a6c0470a 100644
--- a/data/mods/DinoMod/recipes/pets_elephant.json
+++ b/data/mods/DinoMod/recipes/pets_elephant.json
@@ -53,7 +53,7 @@
     "proficiencies": [
       { "proficiency": "prof_chain_armour" },
       { "proficiency": "prof_closures" },
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 }
     ]
   },
   {
@@ -251,7 +251,7 @@
     "book_learn": [ [ "textbook_tailor", 5 ], [ "tailor_portfolio", 5 ], [ "textbook_armwest", 4 ], [ "textbook_armschina", 4 ] ],
     "using": [ [ "sewing_standard", 260 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -273,7 +273,7 @@
     "using": [ [ "forging_standard", 120 ], [ "bronzesmithing_tools", 10 ] ],
     "components": [ [ [ "scrap_bronze", 60 ] ], [ [ "leather_armor_elephant", 1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_redsmithing" },
@@ -293,7 +293,7 @@
     "using": [ [ "blacksmithing_standard", 800 ], [ "steel_standard", 200 ], [ "fabric_leather_fur_hide", 30 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
diff --git a/data/mods/DinoMod/recipes/pets_ostrich.json b/data/mods/DinoMod/recipes/pets_ostrich.json
index f71caba7d8916..ebb5ae55cb117 100644
--- a/data/mods/DinoMod/recipes/pets_ostrich.json
+++ b/data/mods/DinoMod/recipes/pets_ostrich.json
@@ -53,7 +53,7 @@
     "proficiencies": [
       { "proficiency": "prof_chain_armour" },
       { "proficiency": "prof_closures" },
-      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "fail_multiplier": 1.2 }
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 2, "skill_penalty": 0.2 }
     ]
   },
   {
@@ -251,7 +251,7 @@
     "book_learn": [ [ "textbook_tailor", 5 ], [ "tailor_portfolio", 5 ], [ "textbook_armwest", 4 ], [ "textbook_armschina", 4 ] ],
     "using": [ [ "sewing_standard", 260 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
@@ -273,7 +273,7 @@
     "using": [ [ "forging_standard", 120 ], [ "bronzesmithing_tools", 10 ] ],
     "components": [ [ [ "scrap_bronze", 60 ] ], [ [ "leather_armor_ostrich", 1 ] ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_redsmithing" },
@@ -293,7 +293,7 @@
     "using": [ [ "blacksmithing_standard", 800 ], [ "steel_standard", 200 ], [ "fabric_leather_fur_hide", 30 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
diff --git a/data/mods/Generic_Guns/recipes/recipes_firearms_single.json b/data/mods/Generic_Guns/recipes/recipes_firearms_single.json
index 4ab9d5459cf73..15171b5abf863 100644
--- a/data/mods/Generic_Guns/recipes/recipes_firearms_single.json
+++ b/data/mods/Generic_Guns/recipes/recipes_firearms_single.json
@@ -115,7 +115,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "using": [ [ "blacksmithing_standard", 1 ], [ "steel_standard", 3 ] ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "swage", -1 ] ] ],
@@ -139,7 +139,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "using": [ [ "blacksmithing_standard", 2 ], [ "steel_standard", 1 ] ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "swage", -1 ] ] ],
diff --git a/data/mods/Magiclysm/proficiencies.json b/data/mods/Magiclysm/proficiencies.json
index 1a69cf1ad5782..c551168797d74 100644
--- a/data/mods/Magiclysm/proficiencies.json
+++ b/data/mods/Magiclysm/proficiencies.json
@@ -13,7 +13,7 @@
     "description": "You know the basics of manipulating the mana of objects through application of chemical laws.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.3,
+    "default_skill_penalty": 0.3,
     "time_to_learn": "8 h"
   },
   {
@@ -25,7 +25,7 @@
     "can_learn": true,
     "time_to_learn": "4 h",
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "required_proficiencies": [ "prof_alchemy", "prof_metalworking" ]
   },
   {
@@ -36,7 +36,7 @@
     "description": "Working with dragon leather requires a specific set of skills and tools… a set you are familiar with.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 2,
+    "default_skill_penalty": 1,
     "time_to_learn": "6 h",
     "required_proficiencies": [ "prof_leatherworking" ]
   },
@@ -48,7 +48,7 @@
     "description": "Working with dragon scales requires a specific set of skills and tools… a set you are familiar with.",
     "can_learn": true,
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 3,
+    "default_skill_penalty": 2,
     "time_to_learn": "12 h",
     "required_proficiencies": [ "prof_leatherworking_dragon" ]
   },
@@ -61,7 +61,7 @@
     "can_learn": true,
     "time_to_learn": "4 h",
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 2
+    "default_skill_penalty": 1
   },
   {
     "type": "proficiency",
@@ -72,6 +72,6 @@
     "can_learn": true,
     "time_to_learn": "12 h",
     "default_time_multiplier": 2,
-    "default_fail_multiplier": 1
+    "default_skill_penalty": 0
   }
 ]
diff --git a/data/mods/Magiclysm/recipes.json b/data/mods/Magiclysm/recipes.json
index 42f39b37808dd..1a7059a62b70e 100644
--- a/data/mods/Magiclysm/recipes.json
+++ b/data/mods/Magiclysm/recipes.json
@@ -46,7 +46,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.2, "fail_multiplier": 1, "learning_time_multiplier": 0.2 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.2, "learning_time_multiplier": 0.2, "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 16 ] ],
     "qualities": [ { "id": "CHISEL", "level": 3 } ],
diff --git a/data/mods/Magiclysm/recipes/blacksmithing.json b/data/mods/Magiclysm/recipes/blacksmithing.json
index f7206790165f0..2aa62407d2a9a 100644
--- a/data/mods/Magiclysm/recipes/blacksmithing.json
+++ b/data/mods/Magiclysm/recipes/blacksmithing.json
@@ -12,7 +12,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_metallurgy" },
-      { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.5 },
       { "proficiency": "prof_almetallurgy" }
     ],
     "book_learn": [ [ "metal_legends", 4 ] ],
@@ -31,7 +31,7 @@
     "time": "180 m",
     "proficiencies": [
       { "proficiency": "prof_metallurgy" },
-      { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.5 },
       { "proficiency": "prof_almetallurgy" }
     ],
     "batch_time_factors": [ 50, 2 ],
@@ -50,7 +50,7 @@
     "time": "40 m",
     "book_learn": [ [ "metal_legends", 2 ] ],
     "proficiencies": [
-      { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.5 },
       { "proficiency": "prof_pottery" }
     ],
     "qualities": [ { "id": "MANA_INFUSE", "level": 1 } ],
@@ -68,7 +68,7 @@
     "time": "45 m",
     "autolearn": true,
     "qualities": [ { "id": "MANA_INFUSE", "level": 1 }, { "id": "COOK", "level": 3 }, { "id": "DISTILL", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_alchemy", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.5 } ],
     "tools": [ [ [ "surface_heat", 10, "LIST" ] ] ],
     "components": [ [ [ "charcoal", 50 ] ], [ [ "crystallized_mana", 10 ] ], [ [ "denat_alcohol", 10 ], [ "chem_ethanol", 10 ] ] ]
   },
@@ -93,7 +93,7 @@
     "tools": [ [ [ "demon_forge", 30 ] ], [ [ "tongs", -1 ] ] ],
     "proficiencies": [
       { "proficiency": "prof_almetallurgy", "required": true },
-      { "proficiency": "prof_golemancy_basic", "required": false, "time_multiplier": 1.5, "fail_multiplier": 2 }
+      { "proficiency": "prof_golemancy_basic", "required": false, "time_multiplier": 1.5, "skill_penalty": 1 }
     ],
     "components": [ [ [ "orichalcum_ingot", 4 ] ], [ [ "mercury", 4 ] ], [ [ "crystallized_mana", 100 ] ] ]
   }
diff --git a/data/mods/Magiclysm/recipes/magic_tools.json b/data/mods/Magiclysm/recipes/magic_tools.json
index 891658004a671..8c444f398b1fc 100644
--- a/data/mods/Magiclysm/recipes/magic_tools.json
+++ b/data/mods/Magiclysm/recipes/magic_tools.json
@@ -116,7 +116,7 @@
     "difficulty": 4,
     "time": "180 m",
     "book_learn": [ [ "cooking_poison", 3 ] ],
-    "proficiencies": [ { "proficiency": "prof_chitinworking", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_chitinworking", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.5 } ],
     "qualities": [ { "id": "CHISEL", "level": 1 }, { "id": "MANA_INFUSE", "level": 1 } ],
     "components": [ [ [ "demon_chitin_piece", 16 ] ], [ [ "bone_glue", 10 ] ] ]
   },
@@ -137,7 +137,7 @@
       { "id": "HAMMER", "level": 2 },
       { "id": "SMOOTH", "level": 1 }
     ],
-    "proficiencies": [ { "proficiency": "prof_chitinworking", "required": false, "time_multiplier": 1.5, "fail_multiplier": 1.5 } ],
+    "proficiencies": [ { "proficiency": "prof_chitinworking", "required": false, "time_multiplier": 1.5, "skill_penalty": 0.5 } ],
     "components": [
       [ [ "demon_chitin_plate", 24 ] ],
       [ [ "fireproof_mortar", 30 ] ],
diff --git a/data/mods/Magiclysm/recipes/recipe_vehicle.json b/data/mods/Magiclysm/recipes/recipe_vehicle.json
index 6fa863730d083..f02bbd6176278 100644
--- a/data/mods/Magiclysm/recipes/recipe_vehicle.json
+++ b/data/mods/Magiclysm/recipes/recipe_vehicle.json
@@ -14,7 +14,7 @@
     "using": [ [ "welding_standard", 20 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking", "required": false, "learning_time_multiplier": 0.5 },
-      { "proficiency": "prof_welding_basic", "required": false, "fail_multiplier": 1.5 }
+      { "proficiency": "prof_welding_basic", "required": false, "skill_penalty": 0.5 }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 2 }, { "id": "CHISEL", "level": 2 } ],
     "components": [ [ [ "orichalcum_frame", 1 ] ] ]
diff --git a/data/mods/Megafauna/recipes/recipe_others.json b/data/mods/Megafauna/recipes/recipe_others.json
index 005a6ab311f53..c51de951f1dc9 100644
--- a/data/mods/Megafauna/recipes/recipe_others.json
+++ b/data/mods/Megafauna/recipes/recipe_others.json
@@ -12,7 +12,7 @@
     "autolearn": true,
     "qualities": [ { "id": "SEW", "level": 1 }, { "id": "LEATHER_AWL", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "skill_penalty": 0.5 },
       { "proficiency": "prof_leatherworking" },
       { "proficiency": "prof_closures", "required": false, "time_multiplier": 1.5 },
       { "proficiency": "prof_closures_waterproofing" }
@@ -36,7 +36,7 @@
     "autolearn": true,
     "qualities": [ { "id": "SEW", "level": 1 }, { "id": "LEATHER_AWL", "level": 1 }, { "id": "CUT", "level": 2 } ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "fail_multiplier": 1.5 },
+      { "proficiency": "prof_leatherworking_basic", "required": false, "time_multiplier": 2, "skill_penalty": 0.5 },
       { "proficiency": "prof_leatherworking" },
       { "proficiency": "prof_closures", "required": false, "time_multiplier": 1.5 },
       { "proficiency": "prof_closures_waterproofing" }
diff --git a/data/mods/TEST_DATA/proficiencies.json b/data/mods/TEST_DATA/proficiencies.json
index 9010e3ba27022..70aad973726f5 100644
--- a/data/mods/TEST_DATA/proficiencies.json
+++ b/data/mods/TEST_DATA/proficiencies.json
@@ -7,7 +7,7 @@
     "description": "You are beginning to grasp a general idea of writing test cases for CDDA.  Should not show up in game.",
     "can_learn": true,
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.4,
-    "time_to_learn": "24 h"
+    "time_to_learn": "24 h",
+    "default_skill_penalty": 0.4
   }
 ]
diff --git a/data/mods/TEST_DATA/recipes.json b/data/mods/TEST_DATA/recipes.json
index 07ab7a2365795..0df6253b5e141 100644
--- a/data/mods/TEST_DATA/recipes.json
+++ b/data/mods/TEST_DATA/recipes.json
@@ -33,7 +33,7 @@
     "skills_required": [ "melee", 1 ],
     "time": "45 m",
     "autolearn": true,
-    "//proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1 } ],
+    "//proficiencies": [ { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ], [ "pool_cue", 1 ] ] ]
   },
   {
@@ -48,13 +48,13 @@
     "time": "41 d 9 h 36 m",
     "book_learn": [ [ "textbook_armwest", 7 ] ],
     "proficiencies": [
-      { "proficiency": "prof_leatherworking_basic", "fail_multiplier": 1.15, "time_multiplier": 1.1 },
+      { "proficiency": "prof_leatherworking_basic", "time_multiplier": 1.1, "skill_penalty": 0.15 },
       { "proficiency": "prof_closures", "time_multiplier": 1.1 },
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_armorsmithing" },
       { "proficiency": "prof_articulation" },
-      { "proficiency": "prof_quenching", "fail_multiplier": 2 }
+      { "proficiency": "prof_quenching", "skill_penalty": 1 }
     ],
     "components": [ [ [ "2x4", 1 ], [ "pool_cue", 1 ] ] ]
   },
@@ -129,7 +129,7 @@
     "skill_used": "fabrication",
     "time": "5 m",
     "autolearn": true,
-    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 } ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ] ] ]
   },
   {
@@ -159,7 +159,7 @@
     "using": [ [ "cordage", 1 ] ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
     "components": [ [ [ "sheet_metal_small", 4 ] ] ],
-    "proficiencies": [ { "proficiency": "prof_armorsmithing", "fail_multiplier": 1 }, { "proficiency": "prof_articulation" } ]
+    "proficiencies": [ { "proficiency": "prof_armorsmithing", "skill_penalty": 0 }, { "proficiency": "prof_articulation" } ]
   },
   {
     "type": "recipe",
@@ -238,7 +238,7 @@
     "subcategory": "CSC_OTHER_MATERIALS",
     "skill_used": "fabrication",
     "time": "1 h",
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1, "time_multiplier": 2 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 2, "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ] ] ]
   },
   {
@@ -250,7 +250,7 @@
     "subcategory": "CSC_OTHER_MATERIALS",
     "skill_used": "fabrication",
     "time": "10 d",
-    "proficiencies": [ { "proficiency": "prof_carving", "fail_multiplier": 1, "time_multiplier": 2 } ],
+    "proficiencies": [ { "proficiency": "prof_carving", "time_multiplier": 2, "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ] ] ]
   }
 ]
diff --git a/data/mods/innawood/recipes/other/parts.json b/data/mods/innawood/recipes/other/parts.json
index 9960c9de2f3ac..b0d6c23822795 100644
--- a/data/mods/innawood/recipes/other/parts.json
+++ b/data/mods/innawood/recipes/other/parts.json
@@ -27,7 +27,7 @@
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 } ],
     "proficiencies": [
       { "proficiency": "prof_metalworking", "required": false, "time_multiplier": 1.5 },
-      { "proficiency": "prof_plumbing", "required": false, "time_multiplier": 3, "fail_multiplier": 1.5 }
+      { "proficiency": "prof_plumbing", "required": false, "time_multiplier": 3, "skill_penalty": 0.5 }
     ],
     "components": [ [ [ "pipe", 1 ] ], [ [ "scrap", 1 ] ], [ [ "plastic_chunk", 1 ] ], [ [ "pipe_fittings", 1 ] ] ]
   },
@@ -134,7 +134,7 @@
     "using": [ [ "welding_standard", 5 ] ],
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
-      { "proficiency": "prof_welding_basic", "fail_multiplier": 1.5 },
+      { "proficiency": "prof_welding_basic", "skill_penalty": 0.5 },
       { "proficiency": "prof_welding" }
     ],
     "qualities": [ { "id": "HAMMER", "level": 2 }, { "id": "SAW_M", "level": 1 }, { "id": "WRENCH", "level": 1 } ],
diff --git a/data/mods/innawood/recipes/practice/tailoring.json b/data/mods/innawood/recipes/practice/tailoring.json
index 2457433a4d202..af7c31fcd9281 100644
--- a/data/mods/innawood/recipes/practice/tailoring.json
+++ b/data/mods/innawood/recipes/practice/tailoring.json
@@ -9,8 +9,8 @@
     "description": "Practice knitting whatever comes to your mind, from simple forms to elaborate and rich designs.",
     "skill_used": "tailor",
     "proficiencies": [
-      { "proficiency": "prof_knitting", "fail_multiplier": 1, "time_multiplier": 1 },
-      { "proficiency": "prof_knitting_speed", "fail_multiplier": 1, "time_multiplier": 1 }
+      { "proficiency": "prof_knitting", "time_multiplier": 1, "skill_penalty": 0 },
+      { "proficiency": "prof_knitting_speed", "time_multiplier": 1, "skill_penalty": 0 }
     ],
     "time": "1 h",
     "practice_data": { "min_difficulty": 0, "max_difficulty": 1, "skill_limit": 2 },
diff --git a/data/mods/innawood/recipes/tools_electronic.json b/data/mods/innawood/recipes/tools_electronic.json
index 2483689173c9a..26b9a60d3de51 100644
--- a/data/mods/innawood/recipes/tools_electronic.json
+++ b/data/mods/innawood/recipes/tools_electronic.json
@@ -35,7 +35,7 @@
     "autolearn": [ [ "electronics", 2 ] ],
     "book_learn": [ [ "manual_electronics", 1 ], [ "advanced_electronics", 2 ], [ "textbook_anarch", 2 ] ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "SCREW", "level": 1 } ],
-    "proficiencies": [ { "proficiency": "prof_elec_soldering", "fail_multiplier": 1.125 }, { "proficiency": "prof_elec_circuits" } ],
+    "proficiencies": [ { "proficiency": "prof_elec_soldering", "skill_penalty": 0.125 }, { "proficiency": "prof_elec_circuits" } ],
     "components": [
       [ [ "e_scrap", 2 ], [ "glowplug", 1 ], [ "makeshift_transformer", 2 ] ],
       [ [ "copper", 1 ], [ "nail", 1 ], [ "wire", 1 ] ],
diff --git a/data/mods/innawood/recipes/weapon/bashing.json b/data/mods/innawood/recipes/weapon/bashing.json
index dd57dce45f2be..ef1e2790369eb 100644
--- a/data/mods/innawood/recipes/weapon/bashing.json
+++ b/data/mods/innawood/recipes/weapon/bashing.json
@@ -9,10 +9,7 @@
     "time": "25 m",
     "autolearn": true,
     "qualities": [ { "id": "SAW_W", "level": 1 } ],
-    "proficiencies": [
-      { "proficiency": "prof_carpentry_basic", "fail_multiplier": 1 },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
-    ],
+    "proficiencies": [ { "proficiency": "prof_carpentry_basic", "skill_penalty": 0 }, { "proficiency": "prof_carving", "skill_penalty": 0 } ],
     "components": [ [ [ "2x4", 1 ], [ "stick", 1 ] ] ]
   }
 ]
diff --git a/data/mods/innawood/recipes/weapon/piercing.json b/data/mods/innawood/recipes/weapon/piercing.json
index b49c1084dd632..e36ddf3bbb25a 100644
--- a/data/mods/innawood/recipes/weapon/piercing.json
+++ b/data/mods/innawood/recipes/weapon/piercing.json
@@ -12,7 +12,7 @@
     "proficiencies": [
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_redsmithing" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "forging_standard", 1 ], [ "bronzesmithing_tools", 1 ] ],
     "qualities": [ { "id": "CUT", "level": 2 }, { "id": "GRIND", "level": 2 } ],
@@ -34,7 +34,7 @@
       { "proficiency": "prof_metalworking" },
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_bladesmith" },
-      { "proficiency": "prof_carving", "fail_multiplier": 1 }
+      { "proficiency": "prof_carving", "skill_penalty": 0 }
     ],
     "using": [ [ "blacksmithing_standard", 8 ], [ "steel_standard", 2 ] ],
     "qualities": [ { "id": "GRIND", "level": 2 } ],
diff --git a/data/mods/innawood/recipes/weapon/ranged.json b/data/mods/innawood/recipes/weapon/ranged.json
index 33aae782eaf50..1f22a02504eb9 100644
--- a/data/mods/innawood/recipes/weapon/ranged.json
+++ b/data/mods/innawood/recipes/weapon/ranged.json
@@ -23,7 +23,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "swage", -1 ] ] ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 1 ] ], [ [ "sharp_rock", 1 ] ] ]
@@ -52,7 +52,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ] ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 1 ] ], [ [ "sharp_rock", 1 ] ] ]
@@ -81,7 +81,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ] ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 1 ] ], [ [ "sharp_rock", 1 ] ] ]
@@ -110,7 +110,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "tools": [ [ [ "tongs", -1 ] ], [ [ "hotcut", -1 ] ] ],
     "components": [ [ [ "2x4", 1 ] ], [ [ "pipe", 1 ] ], [ [ "sharp_rock", 1 ] ] ]
@@ -133,7 +133,7 @@
       { "proficiency": "prof_blacksmithing" },
       { "proficiency": "prof_gunsmithing_basic" },
       { "proficiency": "prof_gunsmithing_antique" },
-      { "proficiency": "prof_carving", "time_multiplier": 1.5, "fail_multiplier": 1.15 }
+      { "proficiency": "prof_carving", "time_multiplier": 1.5, "skill_penalty": 0.15 }
     ],
     "components": [ [ [ "2x4", 2 ] ], [ [ "pipe", 2 ] ], [ [ "sharp_rock", 2 ] ] ]
   },
@@ -173,7 +173,7 @@
       { "id": "WRENCH", "level": 1 }
     ],
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" }
     ],
     "components": [
@@ -197,7 +197,7 @@
     "reversible": true,
     "decomp_learn": 2,
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" }
     ],
     "autolearn": true,
@@ -213,7 +213,7 @@
     "skill_used": "fabrication",
     "skills_required": [ [ "traps", 2 ], [ "archery", 2 ] ],
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" },
       { "proficiency": "prof_carving", "time_multiplier": 1.5 }
     ],
@@ -237,7 +237,7 @@
     "reversible": true,
     "decomp_learn": 2,
     "proficiencies": [
-      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "fail_multiplier": 1.15 },
+      { "proficiency": "prof_bowyery", "time_multiplier": 1.5, "skill_penalty": 0.15 },
       { "proficiency": "prof_gunsmithing_spring" }
     ],
     "autolearn": true,
diff --git a/doc/JSON_INFO.md b/doc/JSON_INFO.md
index cc6d5453fe769..5d4776f5ba016 100644
--- a/doc/JSON_INFO.md
+++ b/doc/JSON_INFO.md
@@ -1714,7 +1714,7 @@ Crafting recipes are defined as a JSON object with the following fields:
       "proficiency": "prof_knapping", // The id of a proficiency
       "required": false, // Whether or not you must have the proficiency to craft it. Incompatible with `time_multiplier`
       "time_multiplier": 2.0 // The multiplier on time taken to craft this recipe if you do not have this proficiency
-      "fail_multiplier": 2.5 // The multiplier on failure chance when crafting without this proficiency. Defaults to 2.5. Multiple proficiencies will multiply this value. (if all have the default, it's fail_multiplier ^ n, where n is the number of proficiencies that are lacked)
+      "skill_penalty": 1.5 // The effective skill penalty when crafting without this proficiency. Defaults to 1.0. Multiple proficiencies will add to this value.
       "learning_time_multiplier": 1.2 // The multiplier on learning speed for this proficiency. By default, it's the time of the recipe, divided by the time multiplier, and by the number of proficiencies that can also be learned from it.
       "max_experience": "15 m" // This recipe cannot raise your experience for that proficiency above 15 minutes worth.
     }
diff --git a/doc/PROFICIENCY.md b/doc/PROFICIENCY.md
index 41197dc55208f..f2fe923fadba2 100644
--- a/doc/PROFICIENCY.md
+++ b/doc/PROFICIENCY.md
@@ -108,7 +108,7 @@ Within these are the standard list of JSON objects having "type": "proficiency".
     "can_learn": true,
     "time_to_learn": "20 h",
     "default_time_multiplier": 1.5,
-    "default_fail_multiplier": 1.2,
+    "default_skill_penalty": 0.2,
     "required_proficiencies": [ "prof_bow_expert" ],
     "bonuses": { "archery": [ { "type": "strength", "value": 1 } ] }
   }
@@ -126,22 +126,22 @@ Within these are the standard list of JSON objects having "type": "proficiency".
 | `description` | Mandatory | String | Description of what abilities or special knowledge the proficiency entails
 | `can_learn`   | Mandatory | Bool | Whether or not this proficiency can be learned through normal means during the game.
 | `default_time_multiplier` | Optional | Float | Time multiplier for crafting recipes (see below)
-| `default_fail_multiplier` | Optional | Float | Failure chance multiplier for crafting recipes (see below)
+| `default_skill_penalty` | Optional | Float | Effective skill penalty for crafting recipes (see below)
 | `default_weakpoint_bonus` | Optional | Float | Flat bonus to the attacker's skill
 | `default_weakpoint_penalty` | Optional | Float | Flat penalty to the attacker's skill if they lack the skill
 | `time_to_learn` | Optional | time_duration, as a string | The (optimal) time required to learn this proficiency.
 | `required_proficiencies` | Optional | Array of strings | The proficiencies that must be obtained before this one can.  You cannot gain experience in a proficiency without the necessary prerequisites.
 | `bonuses` | Optional | Object, with an array of object as values | This member is used to apply bonuses to certain activities given the player has a particular proficiency. The bonuses applied must be hardcoded to the activity in question. (see below)
 
-### time and fail multiplier
+### time multiplier and skill penalty
 
-Regarding `default_time_multiplier` and `default_fail_multiplier`, these specify the maximum penalty
+Regarding `default_time_multiplier` and `default_skill_penalty`, these specify the maximum penalty
 for lacking the proficiency when crafting a recipe that involves it.
 
-- For proficiencies that represent core basic knowledge and foundational principles, the `time` multiplier should usually be low (1.5 or so), and the `fail` multiplier should be high (1.4 or more).
-- For "flavor" proficiencies that offer a small boost, these should be around 1.5 for time and 1 to 1.1 for fail.
-- Most other proficiencies should be in the 2-3 range for time values and 1.2-1.3 for fail.
-- In general fail rates should range from 1.1 to 1.5, while time rates should range from 1.5 to 5.
+- For proficiencies that represent core basic knowledge and foundational principles, the `time` multiplier should usually be low (1.5 or so), and the `skill` penalty should be lower (0.4 or more).
+- For "flavor" proficiencies that offer a small boost, these should be around 1.5 for time and 0 to 0.1 for skill.
+- Most other proficiencies should be in the 2-3 range for time values and 0.2-0.3 for skill.
+- In general skill penalties should range from 0.1 to 0.5, while time rates should range from 1.5 to 5.
 
 ### bonuses
 
diff --git a/src/crafting.cpp b/src/crafting.cpp
index d0163799c7fb3..9625ab0039295 100644
--- a/src/crafting.cpp
+++ b/src/crafting.cpp
@@ -1061,11 +1061,9 @@ float Character::get_recipe_weighted_skill_average( const recipe &making ) const
                    total_skill_modifiers, int_cur / 4.f );
 
     // Missing proficiencies penalize skill level
-    // At the time of writing this is currently called a fail multiplier.
-    // TK: change the name of this feature to "skill penalty".
     for( const recipe_proficiency &recip : making.proficiencies ) {
         if( !recip.required && !has_proficiency( recip.id ) ) {
-            total_skill_modifiers -= ( recip.fail_multiplier - 1.0f );
+            total_skill_modifiers -= recip.skill_penalty;
         }
     }
 
diff --git a/src/crafting_gui.cpp b/src/crafting_gui.cpp
index 3d4b9541d35f0..676255c9b1af1 100644
--- a/src/crafting_gui.cpp
+++ b/src/crafting_gui.cpp
@@ -209,7 +209,7 @@ struct availability {
     private:
         const recipe *rec;
         mutable float proficiency_time_maluses = -1.0f;
-        mutable float proficiency_failure_maluses = -1.0f;
+        mutable float proficiency_skill_maluses = -1.0f;
     public:
         float get_proficiency_time_maluses() const {
             if( proficiency_time_maluses < 0 ) {
@@ -219,13 +219,13 @@ struct availability {
 
             return proficiency_time_maluses;
         }
-        float get_proficiency_failure_maluses() const {
-            if( proficiency_failure_maluses < 0 ) {
+        float get_proficiency_skill_maluses() const {
+            if( proficiency_skill_maluses < 0 ) {
                 Character &player = get_player_character();
-                proficiency_failure_maluses = rec->proficiency_failure_maluses( player );
+                proficiency_skill_maluses = rec->proficiency_skill_maluses( player );
             }
 
-            return proficiency_failure_maluses;
+            return proficiency_skill_maluses;
         }
 
         nc_color selected_color() const {
@@ -406,17 +406,18 @@ static std::vector<std::string> recipe_info(
                   "for multiple components</color>\n" );
     }
     const float time_maluses = avail.get_proficiency_time_maluses();
-    const float fail_maluses = avail.get_proficiency_failure_maluses();
-    if( time_maluses != 1.0 && fail_maluses != 1.0 ) {
+    const float skill_maluses = avail.get_proficiency_skill_maluses();
+    if( time_maluses != 1.0 && skill_maluses != 0.0 ) {
         oss << string_format( _( "<color_yellow>This recipe will take %.1fx as long as normal, "
-                                 "and be %.1fx more likely to incur failures, because you "
-                                 "lack some of the proficiencies used.</color>\n" ), time_maluses, fail_maluses );
+                                 "and your effective skill will be %.2f levels lower than normal, because you "
+                                 "lack some of the proficiencies used.</color>\n" ), time_maluses, skill_maluses );
     } else if( time_maluses != 1.0 ) {
         oss << string_format( _( "<color_yellow>This recipe will take %.1fx as long as normal, "
                                  "because you lack some of the proficiencies used.</color>\n" ), time_maluses );
-    } else if( fail_maluses != 1.0 ) {
-        oss << string_format( _( "<color_yellow>This recipe will be %.1fx more likely to incur failures, "
-                                 "because you lack some of the proficiencies used.</color>\n" ), fail_maluses );
+    } else if( skill_maluses != 0.0 ) {
+        oss << string_format(
+                _( "<color_yellow>Your effective skill will be %.2f levels lower than normal, "
+                   "because you lack some of the proficiencies used.</color>\n" ), skill_maluses );
     }
     if( !can_craft_this && !avail.has_proficiencies ) {
         oss << _( "<color_red>Cannot be crafted because you lack"
diff --git a/src/proficiency.cpp b/src/proficiency.cpp
index 297991b0198b1..0f9b213f9faff 100644
--- a/src/proficiency.cpp
+++ b/src/proficiency.cpp
@@ -102,7 +102,7 @@ void proficiency::load( const JsonObject &jo, const std::string & )
     mandatory( jo, was_loaded, "category", _category );
 
     optional( jo, was_loaded, "default_time_multiplier", _default_time_multiplier );
-    optional( jo, was_loaded, "default_fail_multiplier", _default_fail_multiplier );
+    optional( jo, was_loaded, "default_skill_penalty", _default_skill_penalty );
     optional( jo, was_loaded, "default_weakpoint_bonus", _default_weakpoint_bonus );
     optional( jo, was_loaded, "default_weakpoint_penalty", _default_weakpoint_penalty );
     optional( jo, was_loaded, "time_to_learn", _time_to_learn );
@@ -110,6 +110,13 @@ void proficiency::load( const JsonObject &jo, const std::string & )
     optional( jo, was_loaded, "ignore_focus", _ignore_focus );
 
     optional( jo, was_loaded, "bonuses", _bonuses );
+
+    // TODO: Remove at some point
+    if( jo.has_float( "default_fail_multiplier" ) ) {
+        debugmsg( "Proficiency %s uses 'default_fail_multiplier' instead of 'default_skill_penalty'!",
+                  id.c_str() );
+        _default_skill_penalty = jo.get_float( "default_fail_multiplier" ) - 1.f;
+    }
 }
 
 void proficiency_category::load( const JsonObject &jo, const std::string & )
@@ -168,9 +175,9 @@ float proficiency::default_time_multiplier() const
     return _default_time_multiplier;
 }
 
-float proficiency::default_fail_multiplier() const
+float proficiency::default_skill_penalty() const
 {
-    return _default_fail_multiplier;
+    return _default_skill_penalty;
 }
 
 float proficiency::default_weakpoint_bonus() const
diff --git a/src/proficiency.h b/src/proficiency.h
index b1d9d8122a063..1ec1c8a8b6717 100644
--- a/src/proficiency.h
+++ b/src/proficiency.h
@@ -76,7 +76,7 @@ class proficiency
         translation _description;
 
         float _default_time_multiplier = 2.0f;
-        float _default_fail_multiplier = 2.0f;
+        float _default_skill_penalty = 1.0f;
 
         float _default_weakpoint_bonus = 0.0f;
         float _default_weakpoint_penalty = 0.0f;
@@ -101,7 +101,7 @@ class proficiency
         std::string description() const;
 
         float default_time_multiplier() const;
-        float default_fail_multiplier() const;
+        float default_skill_penalty() const;
 
         float default_weakpoint_bonus() const;
         float default_weakpoint_penalty() const;
diff --git a/src/recipe.cpp b/src/recipe.cpp
index d00975469839c..30fe0df5d9bb0 100644
--- a/src/recipe.cpp
+++ b/src/recipe.cpp
@@ -498,13 +498,13 @@ void recipe::finalize()
             rpof.time_multiplier = rpof.id->default_time_multiplier();
         }
 
-        if( rpof.fail_multiplier == 0.0f ) {
-            rpof.fail_multiplier = rpof.id->default_fail_multiplier();
+        if( rpof.skill_penalty == 0.0f ) {
+            rpof.skill_penalty = rpof.id->default_skill_penalty();
         }
 
-        if( rpof.fail_multiplier < 1.0f && rpof.id->default_fail_multiplier() < 1.0f ) {
-            debugmsg( "proficiency %s provides a fail bonus for not being known in recipe %s  Fail multiplier: %s Default multiplier: %s",
-                      rpof.id.str(), ident_.str(), rpof.fail_multiplier, rpof.id->default_fail_multiplier() );
+        if( rpof.skill_penalty < 0.f && rpof.id->default_skill_penalty() < 0.f ) {
+            debugmsg( "proficiency %s provides a skill bonus for not being known in recipe %s skill penalty: %g default multiplier: %g",
+                      rpof.id.str(), ident_.str(), rpof.skill_penalty, rpof.id->default_skill_penalty() );
         }
 
         // Now that we've done the error checking, log that a proficiency with this id is used
@@ -746,7 +746,7 @@ std::string recipe::required_proficiencies_string( const Character *c ) const
 struct prof_penalty {
     proficiency_id id;
     float time_mult;
-    float failure_mult;
+    float skill_penalty;
     bool mitigated = false;
 };
 
@@ -760,16 +760,16 @@ static std::string profstring( const prof_penalty &prof,
     }
 
     if( prof.time_mult == 1.0f ) {
-        return string_format( _( "<color_%s>%s</color> (<color_%s>%.1fx\u00a0failure</color>%s)" ),
-                              name_color, prof.id->name(), color, prof.failure_mult, mitigated_str );
-    } else if( prof.failure_mult == 1.0f ) {
+        return string_format( _( "<color_%s>%s</color> (<color_%s>%.2f\u00a0skill penalty</color>%s)" ),
+                              name_color, prof.id->name(), color, prof.skill_penalty, mitigated_str );
+    } else if( prof.skill_penalty == 0.0f ) {
         return string_format( _( "<color_%s>%s</color> (<color_%s>%.1fx\u00a0time</color>%s)" ),
                               name_color, prof.id->name(), color, prof.time_mult, mitigated_str );
     }
 
     return string_format(
-               _( "<color_%s>%s</color> (<color_%s>%.1fx\u00a0time, %.1fx\u00a0failure</color>%s)" ),
-               name_color, prof.id->name(), color, prof.time_mult, prof.failure_mult, mitigated_str );
+               _( "<color_%s>%s</color> (<color_%s>%.1fx\u00a0time, %.2f\u00a0skill penalty</color>%s)" ),
+               name_color, prof.id->name(), color, prof.time_mult, prof.skill_penalty, mitigated_str );
 }
 
 std::string recipe::used_proficiencies_string( const Character *c ) const
@@ -782,7 +782,7 @@ std::string recipe::used_proficiencies_string( const Character *c ) const
     for( const recipe_proficiency &rec : proficiencies ) {
         if( !rec.required ) {
             if( c->has_proficiency( rec.id ) || helpers_have_proficiencies( *c, rec.id ) )  {
-                used_profs.push_back( { rec.id, rec.time_multiplier, rec.fail_multiplier } );
+                used_profs.push_back( { rec.id, rec.time_multiplier, rec.skill_penalty} );
             }
         }
     }
@@ -876,11 +876,11 @@ float recipe::proficiency_time_maluses( const Character &crafter ) const
     return total_malus;
 }
 
-static float proficiency_failure_malus( const Character &crafter, const recipe_proficiency &prof )
+static float proficiency_skill_malus( const Character &crafter, const recipe_proficiency &prof )
 {
     if( !crafter.has_proficiency( prof.id ) &&
-        !helpers_have_proficiencies( crafter, prof.id ) && prof.fail_multiplier > 1.0f ) {
-        double malus =  prof.fail_multiplier - 1.0f;
+        !helpers_have_proficiencies( crafter, prof.id ) && prof.skill_penalty > 0.f ) {
+        double malus =  prof.skill_penalty;
         malus *= 1.0 - crafter.crafting_inventory().get_book_proficiency_bonuses().fail_factor( prof.id );
         double pl = get_aided_proficiency_level( crafter, prof.id );
         // The failure malus is not completely eliminated until the proficiency is mastered.
@@ -891,11 +891,11 @@ static float proficiency_failure_malus( const Character &crafter, const recipe_p
     return 1.0f;
 }
 
-float recipe::proficiency_failure_maluses( const Character &crafter ) const
+float recipe::proficiency_skill_maluses( const Character &crafter ) const
 {
-    float total_malus = 1.0f;
+    float total_malus = 0.f;
     for( const recipe_proficiency &prof : proficiencies ) {
-        total_malus *= proficiency_failure_malus( crafter, prof );
+        total_malus += proficiency_skill_malus( crafter, prof );
     }
     return total_malus;
 }
@@ -914,7 +914,7 @@ std::string recipe::missing_proficiencies_string( const Character *crafter ) con
             if( !( crafter->has_proficiency( prof.id ) || helpers_have_proficiencies( *crafter, prof.id ) ) ) {
                 prof_penalty pen = { prof.id,
                                      proficiency_time_malus( *crafter, prof ),
-                                     proficiency_failure_malus( *crafter, prof )
+                                     proficiency_skill_malus( *crafter, prof )
                                    };
                 pen.mitigated = book_bonuses.time_factor( pen.id ) != 0.0f ||
                                 book_bonuses.fail_factor( pen.id ) != 0.0f;
@@ -1270,9 +1270,17 @@ void recipe_proficiency::load( const JsonObject &jo )
     jo.read( "proficiency", id );
     jo.read( "required", required );
     jo.read( "time_multiplier", time_multiplier );
-    jo.read( "fail_multiplier", fail_multiplier );
+    jo.read( "skill_penalty", skill_penalty );
     jo.read( "learning_time_multiplier", learning_time_mult );
     jo.read( "max_experience", max_experience );
+
+    // TODO: Remove at some point
+    if( jo.has_number( "fail_multiplier" ) ) {
+        debugmsg( "Proficiency %s in a recipe uses 'fail_multiplier' instead of 'skill_penalty'",
+                  id.c_str() );
+        jo.read( "fail_multiplier", skill_penalty );
+        skill_penalty -= 1;
+    }
 }
 
 void book_recipe_data::deserialize( const JsonObject &jo )
diff --git a/src/recipe.h b/src/recipe.h
index 0939bde2d6397..fee12759dbc82 100644
--- a/src/recipe.h
+++ b/src/recipe.h
@@ -51,7 +51,7 @@ struct recipe_proficiency {
     proficiency_id id;
     bool required = false;
     float time_multiplier = 0.0f;
-    float fail_multiplier = 0.0f;
+    float skill_penalty = 0.0f;
     float learning_time_mult = 1.0f;
     cata::optional<time_duration> max_experience = cata::nullopt;
 
@@ -214,8 +214,8 @@ class recipe
         std::vector<proficiency_id> used_proficiencies() const;
         // The time malus due to proficiencies lacking
         float proficiency_time_maluses( const Character &crafter ) const;
-        // The failure malus due to proficiencies lacking
-        float proficiency_failure_maluses( const Character &crafter ) const;
+        // The skill malus due to proficiencies lacking
+        float proficiency_skill_maluses( const Character &crafter ) const;
 
         // How active of exercise this recipe is
         float exertion_level() const;
diff --git a/tests/crafting_test.cpp b/tests/crafting_test.cpp
index f073f2684cf6a..6fff7ed154e1e 100644
--- a/tests/crafting_test.cpp
+++ b/tests/crafting_test.cpp
@@ -725,7 +725,7 @@ TEST_CASE( "crafting_failure_rates_match_calculated", "[crafting][random]" )
     test_chances_for( makeshift_crowbar, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f );
     test_chances_for( meat_cooked, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f );
     test_chances_for( club_wooden_large, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f );
-    test_chances_for( nailboard, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f, 50.f );
+    test_chances_for( nailboard, 54.f, 54.f, 54.f, 50.f, 54.f, 50.f, 50.f );
     // Recipes requring various degrees of skill and proficiencies
     test_chances_for( cudgel, 82.5, 72.f, 50.f, 50.f, 21.f, 21.f, 2.25 );
     test_chances_for( pumpkin_muffins, 92.5, 82.f, 67.f, 50.f, 43.f, 21.f, 2.25 );
diff --git a/tools/json_tools/update_proficiencies.py b/tools/json_tools/update_proficiencies.py
new file mode 100755
index 0000000000000..8d80eb1eb472f
--- /dev/null
+++ b/tools/json_tools/update_proficiencies.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+
+import argparse
+import json
+import os
+
+args = argparse.ArgumentParser()
+args.add_argument("dir", action="store", help="specify json directory")
+args_dict = vars(args.parse_args())
+
+
+def gen_new(path):
+    change = False
+    with open(path, "r", encoding="utf-8") as json_file:
+        json_data = json.load(json_file)
+
+        for jo in json_data:
+            if type(jo) is not dict or "type" not in jo:
+                continue
+
+            if "proficiencies" in jo:
+                for prof in jo["proficiencies"]:
+                    if "fail_multiplier" in prof:
+                        prof["skill_penalty"] = prof["fail_multiplier"] - 1
+                        del prof["fail_multiplier"]
+                        change = True
+
+            elif (jo["type"] == "proficiency" and
+                  "default_fail_multiplier" in jo):
+                jo["default_skill_penalty"] = jo["default_fail_multiplier"] - 1
+                del jo["default_fail_multiplier"]
+                change = True
+
+    return json_data if change else None
+
+
+for root, directories, filenames in os.walk(args_dict["dir"]):
+    for filename in filenames:
+        path = os.path.join(root, filename)
+        if path.endswith(".json"):
+            new = gen_new(path)
+            if new is not None:
+                with open(path, "w", encoding="utf-8") as jf:
+                    json.dump(new, jf, ensure_ascii=False)
+                os.system(f"./tools/format/json_formatter.cgi {path}")