In most cases, the frames of camping trailers are not designed for using leveling jacks on the corners. They tend to twist the frame, which twists the whole construction atop the frame - doors and windows may not open and close properly, and in time, you may compromise sealed joints at corners and where the roof meets the sides. That's why the jacks the factory provides are called "stabilizers." They are only meant to reduce the movement of the unit as you move about in the trailer.
While it is possible to replace "stabilizers" with "leveling jacks," I would not do it, myself. I always use boards beneath the tires on one side to level the trailer side-to-side, then use the tongue jack to level front to rear - then lower the stabilizers. I put a little pressure on them, to ensure they do a good job, but never enough to adjust the leveling. Others may do it, but not me. (I tried once and the door was binding along the outer, bottom edge against the threshhold, so I took some pressure off the offending stabilizer.)
The power stabilizers I have on my 2015 Jay Flight automatically adjust for differences in elevation from side-to-side, but stop when the correct amount of pressure has been applied. Manual stabilizers should be adjusted the same way.
2015 Jay Flight 32RLDS Elite
2012 Chevy 2500HD Crew Cab LTZ (6.6L Duramax/Allison)
Equalizer Hitch (1200# bars)