"Vehicle manufacturers require weight distribution."
How much does GM "Require" for their 1500 and 2500 HD models?
One also could ask how much does GM require for their 1500- and 2500-series SUVs?
According to the 2013 Owners Manuals, the answer is:
"
When using a weight-distributing hitch, the spring bars should be adjusted so the distance {body to ground at front wheel} is the same after coupling the trailer to the tow vehicle and adjusting the hitch.
"
That corresponds to 100% Front Axle Load Restoration.
The Owners Manuals also specify a maximum allowable tongue weight of 1000#.
I've not seen any evidence indicating that the Andersen WDH can achieve 100% FALR with a tongue weight of 1000#, in spite of the fact that it has a tongue weight rating of 1400#.
IMO, anyone who is contemplating purchase of the Andersen WDH should be well aware of its weight distribution limitations.
Ron