VAT on payments on account from a customer are logged on a VAT return when received, as they should be when cash accounting for VAT. When they are then matched in the future to the sales invoice, if it is not the exact amount, it may create an overpayment on the sales invoice, and the VAT on the over payment shows as deduction in Box 1. Can we simply part allocate the payment on account to match the sales invoice value and keep the remainder as a payment on account to match to a future sales invoice so that this issue does not occur on the VAT return.