Conditional Pricing Error?

I'm attempting to use conditional logic on my form to allow the following:
1. A total amount owed is typed in
2. A procesing fee based on a selection from a drop down menu and another field is calculated (ie. The processing fee = (Total Owed * .06)+$25.00 if the drop down is option 1 AND the payment method is credit card. Else, Processing Fee = something else.
3. A subscription based payment is made via credit card with the processing fee charged the first time and a continuous payment after that on a monthly basis.
In order to have only the correct processing fee charged, I am using a different field called "total processing fee" as my subscription setup field for the credit card processing. This "total processing fee" = processing fee 1 + processing fee 2 etc where only one of the processing fees will actually populate due to conditional logic.
All of this 'almost' works and the total processing fee field does have the correct numbers. The issue I have is that despite the fact I have configured the subscription to only use the total fee field, the authorize.net plugin will add ALL of the processing fees, inluding those hidden by conditional logic into a single enormous number and charge it to the credit card. Is this a bug? If not, and it is by design, is there a way to accomplish conditional pricing?
I'm using Gravity forms 1.7.3 and the Authorize.net plugin version 1.3.4
Thanks,
Nate

Thanks Rob, I just submitted a priority request.

Nate