I think much depends on local competition. Where I was taught, there were eight fixed wing schools. Most of them have gone bust since. Some of the instructors were on a £10/day retainer plus £10-20/hr for actual airborne time. That sort of thing will result in the recruitment of instructors with a pretty severe hour building objective. Instructors which are paid something more reasonable are going to be, on the whole, better. Still, each will have a view based on their own experiences.
I don't think +/-800ft altitude hold is acceptable, BTW
How long have these people taken to reach 500hrs???