Bryan, Gerald:
I don't know if this will help, but I have the same coach.
On my '98 Contessa, the performance of the front air bags is this: If I dump air the front lowers all the way down. The rear takes quite a while longer to go right down. When I air up, the front comes up last, by quite a while. So much later that I have actually driven off once before it was all the way up. It did rise the rest of the way within a short while after starting up. If I don't dump, the whole coach will sink overnight, or faster.
I had an air leak that was audible, at the air reservoir. Until I fixed that leak, the rear never went down (or perhaps, it never came up? It seemed to be full height, and that height hasn't changed). I wanted to know how much the trailer hitch went down, so I meaasured, and at the hitch, there was no movement. Now, with the leak fixed, it goes down so the bottom of the mud guard touches the ground, about 3", but when I looked at the bags, they seemed fully deflated.
Levelling is by hydraulic jacks, 1 in front, 2 in rear.
If this issue needs further investigation, I'll be back at the coach in a couple of weeks, so can take measurements properly then.