Transfer days not considered in program RFINTITAR
You set the option "Transfer days" in transaction OB82 but this is not being considered when running Item Interest Calculation (program RFINTITAR).
This is because Transfer days are only deducted for incoming payments. If you do not select them (by using dynamic selections) or when the clearing document is not an incoming payment, transfer days are not deducted.
When you select only invoices and clearing items are not selected, the program cannot determine, whether this is a payment or not or take the document date into account.
When no clearing item is selected, the interests for the invoices are calculated till the clearing date.
For considering the transfer days, you can also use BADI FI_INT_CUS01 in method INT_CHANGE_ITEMS.