Don't do it.
As above, 3 degrees side to side (the fridge) and 6 front to back is max. You said about 3. If it is less than 3 side to side then might be ok, if more then will be bad.
What happens is the liquid will get trapped in the coils when it is off-level and because it does not drip back down into the boiler section and keep it full damage will occur.
A little bit of liquid trapped may or may not be a problem, but do you want to take that $1,500 risk?
I have friend that swears that his fridge can run off-level and he never bothers to level the camper for the fridge. Now he does not know why the fridge will not work.
This process of damage takes time. Damage builds up until eventually, usually on a hotter day, it just will not work.