formula assistance getting an ERROR: Invalid Expression: CASE WHEN {subsidiary}='Parent Subsidiary : ABC' THEN {custcol_date} + {vendor.custentity_time_uk} ELSE 0 END custcol_date is a line level date field on the transaction & time is an integer number on the vendor record.. any help?

It doesn't make much sense to return different data types in a CASE WHEN formula

Try replacing the = with LIKE