I've installed Ubercart Alpha 8 and workflow_ng, but have some problems with tax calculation. Maybe I am using it wrong.

In Store administration > Configuration > tax settings:
I created two items: StateA_tax and StateB_tax

[BTW: I had one item before alpha 8, and it had an entry in the "Area" column. I could not see how to set up this value for the 2nd item, (or even if it important at all), so I deleted item 1 and recreated it, w/o Area value]

In Site building > workflow_ng > StateA_tax:
I created a condition to "check an order's delivery zone", setting the condition to StateA

Similarly for Site building > workflow_ng > StateB_tax: etting the condition to StateB.

Now when I test the Shopping Cart Checkout, when I select StateA, the proper tax appears. When I modify the zone to StateB, the tax for StateB is added, but tax for StateA is NOT removed.

Am I setting it right? What should I do?