Update specification/dimensions/tags.md

Co-authored-by: Udam Dewaraja <[email protected]>

specification/dimensions/tags.md

@@ -2,7 +2,7 @@
 
 The Tags column represents the set of finalized user-defined and/or provider-defined tags assigned to Tag Sources.  Tags are commonly used for scenarios like adding business context to billing data to identify and accurately allocate charges.
 
-A tag is 'finalized' after a single tag value is chosen from a set of corresponding tag values for a single tag key.  Whether a tag key can have multiple, possible values is determined by the Provider.
+A tag becomes 'finalized' when a single value is selected from a set of possible tag values assigned to the tag key at different levels of a resource grouping hierarchy (if supported by the Provider).```
 
 The Tags column adheres to the following requirements: