Why does AlphaCommerceHub allow to void zero amounts?

It is a bug or a feature?

See also:

This is not strictly what you sent in the request. You submitted a CancelPayment without an amount specified. Depending on the provider they will just void the transaction regardless of an amount as only a few support partial reversals. As you did not supply an amount it was considered null and converted to 0 for display. We will review the display of these reversals but functionality is ok

So, «0.00» is an AlphaCommerceHub’s merchant user interface’s bug, and AlphaCommerceHub should display «$161.00» instead for the transaction from my screenshot above?