Found that changing the Decimal(10,8) to Decimal(20,8) fixed an issue I was having in this script when encountering an index range at 100%.

CASE
WHEN Max_Value > 9999999999999999999999999999999999999 THEN NULL
ELSE
CAST(
CASE WHEN (Increment_Value > 0)
THEN (100)(1.0-(CAST(Max_Value-Last_Value AS FLOAT)/CAST(Max_Value-Seed_Value + 1.0 AS FLOAT)))
ELSE (100)(1.0-(CAST(Min_Value-Last_Value AS FLOAT)/CAST(Min_Value-Seed_Value + 1.0 AS FLOAT)))
END AS DECIMAL(20,8))
END AS [Current_Inserts_Used_Pct]