I suggest that you consult with an attorney that practices in the area of automotive law before signing any document that the car dealership now wishes you to sign for the simple reason that the document you previously signed may have been under the penalty of perjury and the one requested to be signed may also be under the penalty of perjury.If you sign the second one which is in conflict with the first, you very well could have serious issues later on with respect to the representations that you made to the dealership when you traded in your former car as to price given to you based upon 50,000 versus 100,000 miles where you could be held accountable for the discrepancy.