well to be honest, that was prob a "go away price"
Discount Tire makes money by SELLING NEW TIRES and selling ROAD SIDE HAZARD plans.
They dont make money flipping your camber tires around. It costs them $10/hour for a tech , so if they charged you $20 or $40 they would prob only be making $15-20 per car.
Its not worth it to them when they sell $5000 in tires a day. Especially if they are busy.
WHat did you expect from a big corp?
Try something a little more mom and pop like GTE.