diff --git a/rollup.go b/rollup.go
index 921367f..7309205 100644
--- a/rollup.go
+++ b/rollup.go
@@ -70,6 +70,8 @@ var rollupFuncs = map[string]bool{
 	"stale_samples_over_time": true,
 	"stddev_over_time":        true,
 	"stdvar_over_time":        true,
+	"sum_gt_over_time":        true,
+	"sum_lt_over_time":        true,
 	"sum_over_time":           true,
 	"sum2_over_time":          true,
 	"tfirst_over_time":        true,