11.5.9 CE Auto Recon matching question

I am implementing auto reconciliation in 11.5.9 oracle financials. The Oracle Cash Management User Guids page 1-11 states  that JE Lines will be matched to bank statement lines when the JE Line Description matches the statement line trx number.

I have developed a custom program that updates the bank trx number on the bank statement line to the description of the JE Line based on the trx amount and date. But when I run the auto reconciliation I get exception errors for 'duplicate journal entries'. I think this is because the JE Line description is the same on all the lines in a particular batch that I'm trying to reconcile. However the dollar amounts for each line are different. I would expect the auto reconciliation program to use the line description, amount, and date to match, but it seems