Apple Store Tax Funny Business?

A friend of mine pointed out that for some reason when he ordered is (wonderful) iPhone 3GS, the Apple Store charged the wrong amount for sales tax.

In Massachusetts, we are lucky enough to pay 5% sales tax. Actually this is going up in a few days to 6.25%.

Anyway, I hadn't reviewed my bill from the Apple Store, but, wouldn't you know, the error shows up in my bill!

If you look at the little screen shot of my bill, indeed, this does not look like a 5% tax to me!

What do you think? 9.8%! Who do I call?