It cannot happen, The report shows you data from CustTrans and in CustTrans there is single field for Amount. It is either AmountCur or AmountMST
There are NO separate fields for debit or credit.
so as data is being saved in single column it is impossible where DEBIT == CREDIT
Also, try to post a journal where DEBIT == CREDIT, you will get answer
if Customer is Credit, you cannot Debit customer same time, usually you Debit to bank or any ledger.
Kindly think and redefine your requirement