My first RV was a tt in 1974 and I always heard that the level had to be right on for the refrigerator to work properly. I used a round bubble level in the bottom of the refrigerator to check for level. Refrigerator never seemed cold enough. I checked the level with a 2 foot level on the floor and it didn't make any difference. Darn thing would never get real cold. Once we went camping and arrived late and didn't have time to set the camper up we just went on to bed. We were leaning slightly to one side, not enough to mess our minds up but the bubble was out of the center of the round bubble level. Woke up the next morning and the refrigerator/freezer had never been that cold before.
After that we always set the camper slightly off to get the refrigerator to cool like we wanted. We had that camper 12 years and the refrigerator never failed us once. We almost always kept it on gas, but it worked ok on electric also.
Next RV was a motorhome. That refrigerator would keep ice cream frozen in the freezer compartment. We always tried to level it close, but we didn't have leveling jacks only a good stock of wood to put under the wheels.
After going 15 years without an RV we bought a motorhome 5 moths ago but I haven't even turned on the refrigerator. We haven't taken it out camping yet. Maybe next week. I can't believe we are retired and never have as much time as when we worked full time.