First, make sure your level(s) reads correctly. Lots of them don't. Easy to do. Place your level on a straight surface and see where the bubble is. The flip sideways. It should read the same. Then flip end over end. Again, it should read the same.
When I got our new to us camper home, I leveled to the existing stick-on levels. When I checked the reefer, it was off. Same with floor. So I got out a 6', a 3', and a 12" level. I measured off the reefer, stove, table, floor and bed. Got it where I wanted it, then screwed on one level I can see in the mirror for side to side, and another on the side for fore and aft. I could move the stick-on levels, so I took them off.
