Although showing these independent truck frame twist test doesn't have any direct connection to towing capacities, we have noted elsewhere that some trucks have derated the conventional towing capacities significantly. Some have the opinion that the derating is related to the truck's frame. You may draw your own conclusions however you wish. We are not making any recommendations or suggesting any conclusions.
(Note: It is reported that the 2017 Ford SDs and are receiving some frame and other drivetrain upgrades. Read here.)
Before You Buy That RV, Truck or Other Tow Vehicle