I guess I have been lucky enough to work on regularly maintained hoists. All I have to do is lube my slides, keep the arms clean, and, as you said, torque the mounting bolts. It was explained to me years ago how to adjust the cables to balance the two sides, but lack of needing to perform this task has caused it to wander from memory. The only issue I have had with my Rotary 12000 lb was a blown hydrualic line, thank fully the hoist was at the position I as able to work at, so no down time, and the locks worked.
At our new shop I get a brand new Bendpack 18000 lb hoist and we will continue from there.
BTW, if he had posted about the floor being sloped, I never would have suggested the cable method. We had a hoist put into our old wash bay and the installer had to shim it up to level, then poured concrete under the posts for support. Do it right...