As it stands currently, you can issue a prepayment against a PO. However, when invoices are processed against that PO, they are automatically 100% applied towards the outstanding prepayment balance available. In many business scenarios, there should at least be the flexibility to adjustment how much of the invoice goes towards the prepayment and how much of the invoice is still to be left as payable to the vendor. Please provide the ability to adjust the purchase order prepayment balance applied to vendor invoices.