In our coach, there is another two-door cabinet structure (3' 6" long) over a chest of drawers and countertop to the fore-end of the four-door cabinet structure (7' 9" long) which is over the head end of the king-size bed. The cabinet structures appear to be totally separate (unattached to each other) yet are snugly placed end-to-end between the two vertical walls of the ~11' 6" long bedroom slide. The only place I can see that either cabinet structure has settled down is at the fore-inward corner (front towards the center of the bedroom) of the four-door cabinet structure. The other three corners of the four-door cabinet structure appear to remain up against the slide's ceiling. And all four corners of the two-door cabinet structure over the chest of drawers and countertop appear, also, to remain up against the slide's ceiling. So... whatever holds that one corner of the four-door cabinet structure over the king-sized bed up against the slide's ceiling has loosened or released or otherwise allowed that one corner to sag about 1/2".
I used a small mirror to look into that fore-end cabinet door (where the sagging is) looking for some ceiling attachment device - none to be seen. I used a mirror to look down behind the front fascia of the cabinet structure (where the sagging is) - no attachment device there either. I am thinking I need to get the advice of someone from the construction process to make this repair or take the coach to Bend (217 miles away) to have someone at BCS make the repair.
BTW, because I am the driver of the coach, I am unable to tell if the cabinet structure moves, bounces, or squeaks while traveling. Its location is about 35' behind the pilot's seat. I have the feeling that whatever is allowing Mike's cabinet structure to squeak is the same problem allowing our cabinet to sag. Our problem is simply older and more "mature" than Mike's problem. I know our sagging cabinet structure at that corner has existed for several years and has not gotten worse that I know of.