Yes, most of the torque being generated at WDH head (within the sockets of the bar ends) is simply being transferred forwards into the shank, NOT going upwards into the hitch ball (where it would increase the force, in pounds, against the coupler).
But I'm sure that it's certainly NOT as simple as "The weight which doesn't go on the front tires or the TM axle still rests on the ball"-- although your TV's rear axle is handling 200 lbs of WEIGHT, it is doing so partly as a result of a torque moment, just like the front axle-- the hitch ball is not centered above your rear axle and the "dead weight" previously located at the hitch ball is being converted into axle loads via many forces and arms of Moment within the WDH.
It's complicated to figure out exactly, because the chains do have some moment of downwards torque happening on the frame's coupler (pulling it down into the hitch head and ball). After your trailer tires have responded to the torque load by taking more weight, the front of the coupler "rests" down a bit, onto the ball. I'm guessing that the angle of the head is an important factor in managing the vertical (ball and coupler) versus horizontal (TV shank) distribution of the twisting forces from the tow bars, but the math is a ways beyond my ability.
As we all know, a 600 lb tongue weight wasn't a 600 lb axle weight when loading a trailer without a WDH-- the front of the TV was unloaded, and the rear axle was handling a lot more than 600 lbs.
The math is really bad. My head hurts.
But thanks again for picture; I'll guess that the changes in weight at the hitch ball are designed to be very small when the head angle is correct and the WDH is properly set, because having the coupler loose from the ball would be a Bad Thing(tm).