I have the same problem. Tomorro I will be getting my interior detailed. When that is finished I will be taking the seat apart to see what needs to be done to level the armrest. I will let you know what I find.
I tried to find a new armrest for my "94" Ranger and I could not find any to purchase. If you have any ideas about getting a new armrest, I would be gratefull to know where to get it...