I treat Core Charge as an Other Charge Type item, because it is a Charge. Make a Parent Level item with two subitems:
Core Charge
Core Chg Refund
Use the Core Charge to Charge the customer on the sales receipt or invoice. Use the Refund item on the credit memo. Set up a custom report that shows only these two items, and now you can see how many/how much, and who, never returned it.
