vw
As soon as the dealer knew you had invested money in having someone check it over, and then you came back to him....he knew that you were satisfied with the tractor. And he prolly figured you knew it was more value than what he was originally asking. So he upped the price, and prolly knows it will be hard for you to walk away from the deal (as you are vested in it now). It's a game, some like to play, some don't. Some know how, some don't.
IMO, that is bs.
I'd offer him 10,500. That's $500 less than his orginal asking price, the cost of the $500 maintenance that was NOT done.
Take it or leave it buddy.