For s slightly different perspective, think of weight ratings in comparison to the highway signs that show a curve coming up, and tell you the speed you should be at to safely make the curve (on dry roads).
It is not a firm speed limit, it is a recommendation.
weight ratings are just that; ratings, not a firm limit.
In fact, my old 1994 Dodge Ram CTD one ton dually was registered for a GVW of 14,000 lbs. Legally, that was the only important number. I chose it because I knew I could never exceed it. AFAIK, I never did, even when hauling hay.