[flybouy]

First off do not rely on "published" numbers, the point of them is to sell a product, period. GM's "new" weight stickers with gooseneck ratings is another sales tool. Any RV has a different loading/hitch percentage to GTW than a generic goose neck used to derive that rating. A flatbed hualing a tractor or a car will have far less pin weight than an RV.

As for the truck, payload is payload doesn't matter HOW the weight is applied, it's about HOW MUCH weight is applied. If that number isn't exceeded then the axle weight ratings dictate WHERE the weight can be applied. It's not a Chinese menu where you can pick WHICH max number you want to not exceed. It's the FIRST of any of those limitations that stop you when it's exceeded.