That bill sounds a bit excessive. Was it just a regular 100hr or were there problems with the machine?
I found the maintenance cost per hour on the 44 to be lower than the 22. Much less unscheduled maintenance on the 44. With only 70hrs on the clock I would of thought that any unscheduled work should be covered by warranty.
A lot of maintenance organisations publish a price guide on each job i.e. 50hr, 100hr and annual. I found that if I gave them a hard time and told them not to do any work above the price guide without my approval the bills seemed to get smaller. Also mentioning other maintenance companies seemed to control the bills.
I think your pants are well and truly around your ankles........