Date of Update for Payments 
For the enhanced payment selection function, the update always occurs on the posting date of the payment – irrespective of the settings in the Update profile. This means that the reduction/payment records for invoices that were cleared by several payments are displayed on the respective date (period) of the payment.
With the Original function for the payment selection, the update is dependent on the settings in the Update profile .
If according to the update profile, payments should be updated with the posting date, payments on the posting date of the clearing document (between invoice and payment) are updated.
If according to the update profile, payments should be updated with the due date, and payments on the clearing date of the clearing document.
If according to the update profile, payments should be updated with the delivery date, payments are converted on the update date of the invoice.

Note that you must modify your system for an update of payments with the delivery date. For more information, see SAP note 371993.
Exceptions when determining the update date for the payment selection create reversals (e. g. clearing resets), credit memos and – if the period-based commitment update (PBET) is active or year-end operations – postings in closed periods, both for the enhanced function for the payment selection and the original function. The payment selection determines the date for these posting as follows:
If a date is defined under Accounting → Public Sector Management → Funds Management → Posting → Tools → Period-based Commitment Update → Date of Update , then this date is used.
If no update date was defined, the date that was entered when the payment selection was executed in the Posting Date of Payments field is used.
If no update date was defined and no date was specified for the payment selection, the system updates these postings on the system date.