CD - Mounting height 50/50 between 10 and 13 ft. New construction drywall, no obstacles, 2 circuits 0-10VDC dimming.
Sounding easy. There will be some time above the ceiling, crawling around routing wire, installing boxes, etc. Time will be spent routing wire to wall boxes for both power and control. All this will likely take longer than the actual installation of the fixtures. If the guy is a pro sparky, he's gonna do it correctly with no half-assing things.
Once he gets into a routine on the panels and kits, it should take about 15 minutes each.
So, it depends on how you count. If you're just counting the time to install a fixture, then $85 for 15 minutes is excessive. But if you add in a few hours of rough-in work, moving tools and ladders around, and even travel time, when zero fixtures have yet to get installed, then the costs pile up.
CD