I think we need to be very careful about the car dealership vs helicopter maintenance hourly cost. A service on my Audi takes 4 hours every 18000 miles: which equates to around 500 hours of driving. At £80 an hour, that's around 64 pence an hour.
For the JetRanger, it takes around 1 hours maintenance for every flown hour (forgetting parts!) so that's around £50 an hour.
Dealerships will charge what they can get away with, as they rarely see cars more than once a year, so £300 doesn't look that bad. And as cars now have longer warranties and have become more reliable, they have had to recover their overheads through excessive charges that bear no relation that what they pay their fitters.
Don't become seasoned to that mindset for helicopters, else we'll all be hoodwinked into accepting car-like rates for our maintenance. Don't forget: for a fully utilised engineer earning £40,000 a year, his element of an hours charge is £20. The rest is overhead and profit.
(Sore subject with me, as my maintainers are trying to enforce a 25% increase in labour rates!!)