Clarification on Tran Code 17 and Tran Code 18

Hello All,

I would like to understand posting of TRAN CODE 17 & TRAN CODE 18. As per my knowledge whenever there is an intercompany transfers happening across two different entity locations, tc37 and tc38 gets posted along with TC17 or TC18 based on the difference between Transfer Price and Selling unit retail of sending location.

Would like to understand the calculation part as how TOTAL_RETAIL for TRAN_CODE 17 & TRAN_CODE 18 gets calculated. As per the base package, below is the formula. But the value we obtain in TRAN_DATA doesn't match with based on formula output.

   if L_tsf_price = L_unit_retail then