See that taper in on the lower 1/2 of your tailgate opening? that started in end of model year 2015 duallys.
I think its to stop the bed cracking at bottom corner of that opening with the weight of the dualey fenders added to bed.
My AF 990 is also tight here. but on the AF they put aluminum angle on the front corners, and if your not careful it can hook on that button at top that is for tailgate lock. And yes my camper moves every time I put it in bed of truck, even with rubber mat and torque lift fastguns that are set correct.
one trick to get it off the edge is to jack up the camper so the weight is off the bed, than and lower the close side first until it starts to put weight on bed, than lower other side to level. (it also helps if you can have someone push on corner of camper to move the needed direction as you lower it :).
I been meaning to measure the space so I can put a board in between wheel well and camper to force camper over some. but once I load the camper, it seems to stay loaded until fall.
I have to mess with this every time I load/unload since I don't have a level space I own.
