Want to remove Surcharge in Partial Refund

Want to remove Surcharge in Partial Refund

Query:

Customer informs that they are able to refund the whole transaction with Surcharge,but partial refunds its not working as expected.

Suggestion:

In the current version of iVend (6.6).The system works like that only.
However, such a scenario can be achieved (removing the surcharge in case of a partial refund) using a custom Addon.