You enter the item and what you paid for it.
...and...if the MI software works the same way as my NC state software does, you come back to the table of items, and then when you hit the "Done" (or maybe "Continue") button...the software asks how much total sales tax you already paid in to those other states...and then they only charge the difference if MI happens to have a higher sales tax.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*