AR Transaction for Equal but opposite receipts

When a payment is made to AR in error we request a transfer from AR to the correct place (eg Council Tax or Housing Rent, etc).  This is processed through our Cash Receipting system. To balance the income for any day, we create a Manual receipt for the initial payment and then when the transfer is processed, we reverse the original receipt so that we maintain an audit trail.

Example : recently had such an occurrence when £5 was receipted as an AR receipt in error and therefore included in the Lockbox for the day.  This amount was subsequently transferred out of AR, but on the day the transfer was made, another receipt was also paid, quoting exactly the same reference number and again for £5 exactly.  Our in-house program which take the Cash Receipting file and turns it into an Oracle Cash File, has a line of code which tells it to ignore any equal but opposite transactions for exactly the same amount and same reference number.  We're not sure