If you depend on a little 2" diameter round level to level anything and you think it is accurate you are so wrong.
You would be far better off using a 2' level on the floor.
I adjusted my 5er one time with a laser level so the bottom of the frame was level. I then glued on two Hoppy levels one by the leveling controllers and one under the overhang on the front. I taped them in the level position and removed the tape a few days later when the adhesive was set.
So when I pull into a camp site I look at the level under the front that reads side to side and guesstimate how much blocking it will take to being it ip to level. Once that is done I remove the TV from the RV and adjust the front to back level.
This way my RV is always perfectly level.
I carry 10"X10" plywood blocks of varying sizes from 1/4, 1/2, 3/4, 1 1/8" and also a couple 10" long 4X10's for those really out of level conditions.
Lazer levels are very inexpensive these days and they will come in handy for example then the wife says the painting is not level!