I'd like to see the contract. Sounds like a rate buydown. If it is and you don't keep the car for the full term of the loan for whatever reason (sold it, had it stolen, totaled...) you would have been better off to have gotten the contribution amount needed for the buydown taken off the price of the car in the first place and financed at the actual rate the lender gets. AHFC lowest posted rate currently 2.9%.
Just remember, there's no such thing as a free lunch.
