Interest charge on late payment Calculation FI-CA

Dear All,

We have a requirement where a customer does payment after due date then interest is required to be posted for late payment done. However, calculation of Late payment interest applied is bit tricky. Below is the logic we are required to configure for late payment interest:

• Calculation of Late Payment surcharge in Rs. = B* Invoice amount
• B= Round( A*(SBAR Rate+2%)/52,5)
• A=Round( ((Date of Payment)-(Due Date)/7),0)

How can we achieve above requirement ?

Thanks

Viraj.