Tax on Parts Blank Title 118956

I want to be able to mark a family of parts that are taxable irrespective of the customer they are sold to and what other tax obligations that customer may have. (I collect different rates of taxes for some of my customers which I have Tax Liabilities assigned in the customer masters with the appropriate rates.)
I set up a a Tax Product Category and assigned a Tax Type to it. The Effective Rate on that Tax Type is the required 2.3%. Then added the Product Tax Category to one of the selected parts in the part master. When I add an order for the part, that tax category is drawn from the part master and shows on the order line, but the tax is not calculated on the order summary or resulting invoice.

First, am I correct in assuming that is the way it's supposed to work? And if so, any ideas on what I am missing?