We keep running into an issue with our capital projects, where we have a PO with special items on it, fully received, that we then receive partial invoices on. These partial invoices match, are approved, and close the line, and then we receive an invoice for the rest of the amount. Our current business process is to have our Procurement staff re-open the PO at this point, change the original line to the partial invoice amount, and then put the new invoice amount onto a second line. When they try to release the PO, they get an over budget message and cannot release the PO (all our Capital projects are locked down to avoid going over budget), even though the PO total hasn't changed, and exactly equals the remaining budget. As far as I can tell, by re-opening that closed line, it tries to release the whole PO amount against a budget amount that only equals the total of the new line.
I keep thinking there has to be a better business process than what we are doing, but I'm not sure. How are others handling capital PO's and invoices?