Invoice "Tax" line inclusion is redundant with only a single State Sales Tax (%)

Our sales only require a single state sales tax when shipping in-state. So the invoice showing two lines

Michigan Sales Tax (6%)

                                Tax

seems like it comes from Monty Python's Department of Redundancy Department.

I understand its use in areas that may have multiple taxes (city, county, state, & whatever) to provide a Total Tax figure, but it is something I've never seen on any order or invoice before.

It is a bit confusing at first glance and forces a customer to do some quick mental math to make certain they weren't overcharged.