I'm having what I would call a similar problem with the Dometic in my new EC.
My 2003 AF and 2008 Lance didnt really care if they were all that level regardless of what the books said. The EC seems very particular. As in I have to be within ONE degree of level or it doesnt cool properly. Thats HUGE problem when driving or even in my driveway that is only 3.5 degrees. A two hour road trip pulls the temp from 32 to 40 degrees. Additionally if I dont block up the front end to less than 1 degree(ONLY about 2") in my driveway it stays around 50 degrees. Think about that, I cant even park in a parking lot that is less than 2 inches from level or it doesnt operate right.
I'm pretty sure my old manuals said within 5 degrees of level, the new dometic book says within "a few degrees"
Is your freezer getting as cold as it should? mine gets perfectly cold regardless of the angle. I was told this was an indication that the unit isnt level enough.
I'm about to take it to the dealer for work so I dont have any answers for you.