Due Date for net payment not calculated properly

Hi

I need to calculate netpaymentdue date based on baseline date and payment terms (based on account type K).

I could not find any FM that directly calculates it.

So,I have used to following logic to calculate:

FORM net_duedate .

   DATA:i_faede TYPE faede,
        e_faede TYPE faede,
        i_t052 TYPE t052.

   CLEAR:i_faede,
         e_faede.

SELECT SINGLE ztag1 ztag2 ztag3 FROM  t052 INTO i_t052
        WHERE  zterm  = i_pedidos-zterm.


   i_faede-koart = 'K'.
   i_faede-zfbdt = i_pedidos-eindt. "baseline date
   i_faede-zbd1t = i_t052-ztag1.
   i_faede-zbd2t = i_t052-ztag2.
   i_faede-zbd3t = i_t052-ztag3.

   CALL FUNCTION 'DETERMINE_DUE_DATE'
     EXPORTING
       i_faede                    = i_faede
*     I_GL_FAEDE                 =
     IMPORTING
       e_faede                    = e_faede
     EXCEPTIONS
       account_type_not_supported = 1
       OTHERS                     = 2.
   IF sy-subrc <> 0.
* Implement suitable error here
   ENDIF.


   IF sy-subrc EQ 0.
     i_pedidos-znetdt = e_faede-netdt.
   ENDIF.

However , the above code is not working fine.

For Payment term: DL60 (Within 60 days Due net)  and for Delivery date: 07.11.2014 , due date is calculated as 07.11.2014 whereas it should be

06.01.2015.

Can anybody help me correct the code?