I can't tell any difference and I'm pulling a 5,000 lb camper. One thing I have found to unhook the camper I raise the camper up couple inch's then lower the truck to pop it off the ball. My experience as I keep raising the camper the rear of the truck comes up with it, but I always unhook with the engine off, may be why it doesn't auto level?
I haul some heavy freight in my truck with the factory air suspension. But I balance it pretty well also. Use every inch of the truck available most times.
The air suspension limits unnecessary motions somewhere after 1000-1500# payload or so where it will not let you go into offroad 1 or 2.
But it will still go into Aero mode on the highway.
But I do get the dummy light on the dash for payload capacity but I've hit the scale when it's up and it's only when I exceed 10,000#
But my gross is about 6800 with two people and full tank of fuel. Door states payload capacity of 714# but again. I handle 3500# of payload. IN THE TRUCK. And once I break 10k I lose Aero mode but that's it. And well I really piss off my factory Goodyear SR-A's. But I'll be going to BF Goodrich 10 ply's when I get through these tires.
So the factory air suspension handles A LOT of weight.