Bill Discounting

Hello all, How is the scenario for bill discounting be handled in MBS-3.60.In version 3.60 cust. ledger entry table, what are the following fields for? Closed by Entry No. Closed at Date Closed by Amount Closed by Amount (LCY) Calculate Interest Closing Interest Calculated im using cash receipt journals.in that.,I have added a field called “actual amount received” to capture the actual amount recd. from the bank.also,I calculate the difference between the amount suggested by the system when i use the apply entries in the cash rect.journal.I transfer the actual amount recd.from the bank to the amount column so that the amount gets reflected in both customer and bank ledger entries. However, when I select the apply entries the second time for the same customer, it shows me that the difference amount is still remaining.However, I have made sure that the "open " field is unchecked. This is correctly reflected in the bank ledger entry. KINDLY HELP… iS THERE a better solutions for this!!! thanks ramya