Cash discount and exchange rate difference postings take their business area from the customer/vendor item they originated from. If this item is posted without a business area and the business area is only determined subsequently by means of a transfer posting to the general ledger, you also have to carry out this subsequent step for the cash discount and exchange rate postings.

The bank item is currently posted without a business area (unless one is assigned manually). There is also no standard function that assigns the bank items to the business areas of the cleared customer/vendor items.