Expedition Towing Camper

Your dealer is blowing smoke! The WD hitch does NOT reduce the tongue weight. All it does is move some of the weight off of the rear axle and moves it back to the front axle and some back to the trailer axles. This does not change the tongue weight at all. It stays the same and if it is too light to begin with the trailer will have a tendency to sway. If too heavy you could break things on the tow vehicle. The WD hitch's main job is to restore the weight back to the front axle of the truck that was removed when you put the tongue weight on the ball that is located some distance behind the rear axle (think fulcrum)

Take a look and study the first post in this thread for information on how a WD hitch works so you will be armed to let that dealers salesman know he doesn't know what he is talking about. All he is interested in is selling you a vehicle.
Barney