What I found with mine is if the front starts out higher than the back when the back jacks come down and level side to side and raise the rear the front jacks may not be touching the ground at all. I re calibrated it about 5 times and called Power Gear tech support the guy told me that was normal for my leveling system and if I wanted the front down to run them manually.
Now if the front is low it will have all 4 jacks down after leveling. It is no big deal now that I understand how it works but when I first got the coach and leveled it at the house it did what I explained above and I thought something was broken. The tech told me the newer models test each jack after the leveling procedure to make sure they are all in contact with the ground but not the older ones.