Your area is a high labor rate area and resurfacing of rotors definitely adds to the labor total.
Even with machine work factored in it sounds a bit high to me.
If they’re down to 3 MM then they’re due. You should price this job around at an independent shop and factor in new rotors for the job instead of machining the old.
There’s nothing wrong with machining them unless they’re cut underneath the minimum thickness or someone is doing a so-so job of the machine work.
When weighing the cost of machining rotors it’s often more cost effective to just replace them.
Hope that helps.