Especially since they are paying the mechanic peanuts in comparison. Gen oil/filter change $28 myself. Grease is cheep $8, engine oil, and all filters $200 at most, but your paying to not get your hands dirty and convenience costs. I know my rig isn't a MH but I have all the same expenses as you mostly.
2014 Palomino Columbus 3650TH
435AH 12V VMax Charge Tanks, 520 watt Monocrystilline Solar Array, Morningstar MPPT TS-60 CC,Morningstar Remote,Cotek True Sine Wave Inverter,Cotek Remote Controller,50amp Progressive Hardwire Surge Protector
2015 Dodge 3500 6.7L 4X4
2011 CanAm Commander XT 1000