As your code contains nothing which deals with the 5/10 dollar increments, I'd say that you were right in your assessment 🙂
Try this
CREATE FUNCTION dbo.fn_ck_newBidIsHigher

Shows how often I create UDFs (they are notoriously bad performers, in case you did not know).

CREATE FUNCTION dbo.fn_ck_newBidIsHigher
(
  @auction INT
, @bid  NUMERIC(8,...

Try 
If (condition) 
 Return 1
else
 Return 0;

Please add another screen shot with the Result Set node selected.
Also, are you using an OLEDB or ADO connection?

This statement is false:

In case you have not solved this yet, please try the following:

RIGHT( (DT_WSTR, 15) [PCMRetrievalCode] , LEN ( (DT_WSTR, 15) [PCMRetrievalCode] )- FINDSTRING( (DT_WSTR, 15)[PCMRetrievalCode]...