Finanssiala - AOS2
Table of contents
Rules and definition
AOS2 (additional optional service) is an optional extension to EPC's rules regarding the usage of Remittance Information, increasing the maximum number of the Strd elements from 1 to 999 and the allowed size of the element from 140 to 280. However, only Finnish banks are able to accept AOS2 structured messages.
Without AOS2, due to Strd's size restriction, the transaction block has room to transfer only one reference number. With AOS2, it's possible to send multiple invoices and credit notes along with the reference numbers.
FA has a set of rules regarding correct usage of AOS2. The rules are shown in this graphic table:
The structure and element names are for pain.001.001.03, however the usages of rules apply to pain.001.001.02 as well.
*Rule 1: The value of InstdAmt must be equal to the combined value of the sum amount of all invoices minus the sum amount of all credit notes.
*Rule 2: The combined value of the sum amount of all invoices minus the sum amount of all credit notes must be positive.
The table includes four different cases. They are listed and explained below:
Case 1: Normal invoice with invoice number
Case 2: Normal invoice with ISO 11649 creditor's reference
Case 3: Credit note with invoice number
Case 4: Credit note with ISO 11649 creditor's reference
The "Values"-column refers to the valid values of the elements. The "Max"-column refers to the maximum occurences of the element.
The value "CINV" refers to an invoice and "CREN" to a credit note.
If AOS2 content is sent to banks not supporting AOS2, usually only the Ustrd field is transmitted forward.
One invoice payment is never done with AOS2 but instead as normal SEPA credit transfer. This means that an AOS2 transfer must contain at least one credit note.
The interpretation of these rules may vary from bank to bank.