I just wanted to add something to this post that I found interesting. Some people have wondered how the Chevy could be rated so close to the same GVWR as the Ford but ride softer. I did some research on this and found out that the Ford front GAWR is 5000 and rear GAWR is 8500. Even though the GVWR is 12500 the axles add up to 13500. The Chevy front GAWR is 4700 and the rear GAWR is 7500. This adds up to the rated GVWR of 12200. So even though you should not load more than the factory GVWR the springs in the ford are rated for 1000lbs more and hence the stiffer ride. And maybe the reason some people say its safe to overload your ford but not your chevy.
Edit:
After taking delivery of the Chevy I found a label on the driver door that says GVWR 12300, GAWR Front 4300, GAWR Rear 8600. This differs from the spec sheet of the cutaway online so now I dont have a clue why it feels softer.