I've recently paid as much as $200 for 1 hour with nude, MT, and HE here in San Diego. (For comparison, escorts here run $250 to $300 per hour.) I have no problem paying higher prices for a masseur who is sexy and skilled at what he does. Maybe it's just me, but I actually find myself a little more drawn to the guys who charge $150+. Seems like they can see fewer clients and still earn a good living. I much prefer that to being the 5th or 6th client of the day for a cheaper masseur...
As for the OP's post, I hate upselling, and I agree that $50 just for nudity seems a bit high. Some guys charge $30-$50 more to go from "body work" to "erotic massage." I don't mind paying that because it often includes full nudity, MT, and HE.