AP interface (APXIIMPT) don't accept some price corrections

Hello all,

I hope you can help me out with this issue:

When you match an invoice to a purchase order and the unit price of the invoice is higher then the unit price of the PO, then the system applies a price hold. We use a price correction when a supplier sends an invoice for a change in unit price for that invoice. Sometimes we faced with the problem that the supplier corrects the whole unit price. For example:

PO = 1 X 630 (unit price)

Invoice = 1 x 700

Creditmemo = 1 x -700

When we manually match the invoice in Oracle, there is no problem. The price hold will release after recording the creditmemo. But when we use the AP interface (APXIIMPT) in the validation we get the error "NEGATIVE QUANTITY BILLED'. When we use a quantity correction the price hold will not release.