Somehow it often escape the attention that weight is not the only thing.
I could load 4500 lb of gravel on my F250 flatbed just fine, as I put most of it behind the cabin.
The 4200 lb camper overloaded F250 rear axle pretty badly as the center of gravity went on the axle.
Also there is more technical details beside 1/2 ton v/s 1 ton.
My present F350 come as cab&chassis. Not only the springs on it are heavier than on older F450 I used to have, but longer wheelbase makes it WAY easier on camper weight distribution. I am actually putting the camper with a foot space in front of the bed to have storage space for small generator and gasoline.