Dealership Incorrect Contract

I am active duty military and currently stationed in Pensacola, FL. I purchased a new car here from Nissan and traded in my old car to them. The contract was supposed to be made using Ohio state taxes so I could register my car in Ohio where my old one was. The dealership used a 5% tax rate (Floridas tax rate) instead of Ohio's 7%. Ohio will not register the car until I pay the difference to them. Should this be my responsibility to pay even though it was the dealerships mistake on the contract? My contract says 5%, do they have the right to change it now to 7%?

I like to be on the consumers side, but, why did you not bring up this point when you signed the contract did you not notice the 5% ? - dealer is in the clear, pay the 2% and may you enjoy your investment for a long time to come.