Part payments to Sales/Purchase invoices will be split proportionately and apply to your VAT return. In this instance, we can see that your credit, part paying the bill, although showing on the ledger correctly, has not been allocated to the bill. To allocate the credit please follow the steps below:
From the DPS Home Screen click Client Postings.
Click Office Receipts and Allocations.
Tick the bill and the credit items to allocate, then click Allocate.