Round up / Round down bug

Web app consistentlyly adds or removes a penny after making changes to a saved order. I had a balance that needed changed so I added a negative amount to one of the lines on an order that had already been installed and completed in MBC. The amount that was paid by the customer was $496.83. When I modified it, the amount showed correct on the order. When I went to receive payment, it had changed to a penny less. Then when I went to apply the check, it showed the old amount due as the default for the check payment. See attached pictures with customer information included.