$35 to take off or put on snow tires is HARDLY overcharging.
Into the shop, onto the hoist, up in the air, remove wheel covers if so equipped, and wheel locks if so equipped, remove 4 wheels, install
4 wheels, lower the hoist and torque all 16 or 20 (or 24) lugnuts, install wheelcovers if so equipped, off the hoist and out of the shop, plus the required paperwork is a GOOD half hours work.They need to rent, (or pay for + taxes) heat and maintain the shop, run and maintain the hoists and compressor, pay the mechanic a living wage as well as unemployment insurance, workmans compensation and any other benefits, and still make a small profit. At today's rates, $75 an hour is not going to leave much left over