Why there is no option to write-off minor amounts in the AP invoices

Hi,

We have an invoice against which a prepayment is applied to. The problem here is that the prepayment amount is 1 Rupee less that the total invoice amount.

We would like to write off this 1 rupee from the invoice so that the invoice would not appear in the PPR and also various reports.

Is there a particular reason why there is a functionality to write off amounts in Receivables but not Payables.

Thanks,

Shankar