AbleCommerce Shopping Cart Software

If a customer returns and items for exchange and the new order amount is greater than the new order, how do you apply a balance to a new order to correctly indicate the balanced owed?

The order balance will automatically adjust as items are added or removed from the order. You should see the order total become either positive (customer owes additional monies) or negative (refund is due to the customer) at the top right of the order details page.

If you're trying to just zero-out the order back to a zero balance due, I usually add a credit or charge line item to the order for the offsetting amount.