I have a 2012 Forest River Salem 27DBUd 27ft travel trailer. I have less than 2000 miles on the tires. They were installed at the factory and filled with nitrogen. The tires on the passenger side have all the tread worn off on the outside edges only, 1 had to be replaced already, the other side is cupped. I took it to the dealer, they did a laser alignment, said the rear axle is 1/4" out of alignment, I would need a lift kit and 4 new tires and have it set to my truck again, at a cost of over $1200.00. Does this sound normal? and should this not be a factory issue ?