I've never seen/heard of an RV leveling system designed to actually lift the rig off the ground for maintenance. I have seen a few Class A's with the front tires in the air due to the levelers, but not trailers.
I'd use the leveling system only for stability while the bottle jack has it up in the air. I would NOT jack it up with the bottle drop the levelers, and pull the jack out. I'd expect bad, bad things to happen if you did that.
My theory is, ain't no such thing as too many stabilizing props while _I'm_ under there crawling around!
