Meh. About right for nice rims and low pros. Nobody wants to take the risk of it without getting paid for it. Can't blame them one bit. I just paid 247 iirc for four tires mounted and balanced. No dismount. Dealers just charge more an hour.
I agree with getting paid for the risk but going strictly by number doesn't constitute low profile, figure the sidewall is basically the same on a 315/35 and a 275/40 or a 245/45 but normally the 315 will cost more to mount