If you have activated the setting Manage automatic set-off for on account payments during invoicing under the heading Invoice under the Sales tab in the Settings procedure, you will see this alternative.
If an order number has been selected for the on account payment you can here also select that there should be automatic set-off. This means that when a customer invoice is printed and approved a check will be made to see if the customer has made any payments in advance on the order via on account payments in the accounts receivable. If so, the printed invoice will automatically become partially paid with the amount that the customer has paid in advance. Incoming payment records will then be created that automatically becomes set-off against the printed customer invoice. Customer invoice ledger records will also be created. Incoming payment and ledger records that have been created via automatic set-off become marked with "SOF" and italics in the accounts receivable ledger and incoming payment ledger.
The automatic set-off function is mainly intended for companies that use the MONITOR system in countries where it is not allowed to edit advance invoices ahead (for example using invoicing plans).