OBI Report Query. Formula

Summary:

Hi All, I am having trouble getting a formula working.

Background: we have two related numeric flex fields.

Requisition Flex Field - FTE Requested

Submission Job Offer Flex Field - FTE Offered

What I need to do is get all the FTE Requested from requisitions, and Subtract All the FTE offered

This works on a line by line (requisition by requisition) status, but not once I try to total rows.

These negative amount are perplexing me.

However, at the individual req level, this works

My Formula

FTE Requested: (Cast("Requisition Flex Fields"."UDF15" as double))

FTE Offered: Sum(Cast("Submission Job Offer Flex Fields"."UDF8" as double))