Related to this topic, I was at Prevost NJ for 3 days solid while they tried to track down why by bags were falling and the coach wouldn't stay level. After replacing one part after the other including the Norgren valves there was still no improvement but I got a lot of "Well, those were bad anyhow and also needed to be replaced". On day 3 or 4, I was letting myself into the coach and I heard a hissing noise. I got the so called mechanics attention to it and after further investigation, it was found that the air operated strut that works the recess floor was leaking air and that strut was defective. This was a converter item and Royal had tied it into a part of the air system that was directly tied into letting the air bags leak out and fall.
For what it's worth to the issue of problem solving and wasting money.