How to Issue a Final Invoice After an Advance in KSeF

A final invoice after an advance in KSeF should not be treated as another ordinary sales invoice. If earlier advance invoices do not cover the full payment, the final document settles the entire transaction and reduces the remaining amount by earlier advances.

In the FA(3) structure, remember the simple rule: an advance invoice is type ZAL, and a settlement invoice after advances is usually type ROZ. The rest of this article uses the business names: advance invoice, settlement invoice and final invoice.

The main risk is double settlement of the same sale or no link between the final invoice and earlier advance invoices. Before submission, collect invoice numbers, KSeF numbers, amounts, VAT, dates and UPO confirmations.

A final invoice after an advance is used when the customer paid part of the price before performance and the remaining amount must be settled after the service or delivery. The advance invoice alone does not show the full final settlement.

If the customer paid 30% before delivery and 70% after delivery, the first payment may be documented with an advance invoice, and after the transaction is completed you may need a final invoice. If there were several advances, the final document should refer to the full set of earlier invoices.

If the advance covered the full payment, do not mechanically issue another invoice just because the project ended. That case should be checked with accounting, because an additional document may duplicate the sale instead of organizing it.

An advance invoice and a settlement invoice describe two different moments of the same transaction. The advance invoice documents payment received before performance. The settlement invoice appears later, when the transaction is performed and the full value of the order or contract must be settled.

In practice, the advance invoice answers how much the customer paid before the service. The settlement invoice answers what the full transaction value is, how much was already settled with earlier documents and what remains to be paid.

The broader distinction between invoice types is explained in Types of invoices in KSeF, and the advance process itself is described in Advance invoice in KSeF.

In KSeFGPT, issue the final invoice after an advance in Invoices > Issue > Invoice. In the Invoice type section, select Settlement (ROZ), not Basic (VAT) or Advance (ZAL).

Then complete the seller, buyer, invoice number, dates, line items and final values. In the settlement data, keep the link to earlier advance invoices: their numbers, KSeF numbers, amounts and dates.

Before submission, check the preview and XML. If the amounts do not match the advances, stop and explain the difference with accounting. After submission to KSeF, store the KSeF number, status and UPO for the settlement invoice.

The first mistake is issuing an ordinary VAT invoice instead of a settlement invoice. It may look correct in a PDF view, but it does not clearly settle earlier advances.

The second mistake is deducting only one advance when the customer paid several times. The third is missing KSeF numbers or UPO in the internal register. The fourth is issuing a final document while the status of an advance invoice is still unclear.

If you discover an error after submission, do not rewrite the history manually and do not issue another ordinary invoice without analysis. Start by determining whether a correction is needed. The general process is described in Corrective invoice in KSeF.