Using RF Goods receipt with excess Quantity and less Quantity

I have a requirement where I need to complete my Over receipt and under receipt (i.e; to receive more than the delivery quantity and less than the delivery quantity) using RF.

For this, I have created a Put away Task (HU WT for bulk storage type) and used the exception code DIFD (DIFS also I tried) in the task and reduced/increased the delivery quantity in GUI screen. Whereas I try the same exception code in RF it throws me an error "E: Exception code DIFS cannot be used (/SCWM/EXCEPTION003)."

I have assigned the process code to the exception code "DIFS" and Internal Process code as "DIFS". I have also used "DIFF" as Internal process code but no luck. Please suggest.