Solved: lookup fails on collection but succeeds with sql table

I have the following LookUp formula that runs against a SQL table to find Cost information. Filter conditions return a unique Cost.

            LookUp(
                SubRates,
                BuilderID = CurBuilder And Class = "Steel"
             
                 And SubCode = "TestSub" And Task_No = 2,
                Cost)
This works.
 
However, since it is a very large # records in SQL table, I first create a filtered collection into colSubRates
 
            LookUp(
                colSubRates,
                BuilderID = CurBuilder And Class = "Steel"
             
                 And SubCode = "TestSub" And Task_No = 2,
                Cost)
 
This does not work.
 
Ideas?
 
Thanks,
 
Larry Knudson