In my experience the so called trained manufacturers engineers are not always that great at repairing their own product either, we have had the manufacturer of German yellow trucks, engineers in the UK go to jobs we have had to end up sorting because they either were struggling or just part fitting until the truck is repaired on their own product!
We have done motor, strip skim and rebuild jobs for £800 rather than £4000 quoted to just replace, customers cant and should not put up with this way of working and having to pay for the lack of common sense of so called factory trained engineers!! so what happens when the crap hits the fan with them??