Vendor invoices are registered and then transferred to the invoice pool for approval and posting. If the invoice date is changed in the invoice pool, the voucher number is updated. This means that the invoice voucher is not the same as the invoice register voucher for that invoice.

When the vendor invoices are transferred to Intrastat, those whose invoice voucher do not match their invoice register voucher are not transferred. If vendor product receipts are also transferred, then invoices whose invoice vouchers match their invoice register vouchers are transferred twice.