The other thing you should check is that the Tax is set to go to AP.

Maintain > Tax Groups > Edit

Select the Jurisdictions from the drop down box and make sure that the "Costing Method" is set to Accounts Payable (or "Both AP and IC" if applicable).

If this is set to "None, GL only" the Plus tax will show $0, even though you will see the taxes displayed correctly on the right.