With this setup, what results is actually a double fulcrum action. Not only does the shaft have a gentle bend in it, placing great stress on the top side of the tunica (the septum in particular), but also the skids of the hanger attempt to swing down and into the fulcrum. With the hard plastic in position, the skids are firmly halted, and you get greater stress on the top of the shaft. The stretch is incredible.
The position of your butt on the chair seat matters greatly. You can scoot down in the seat, with your pelvis tilted back, and the hanger sticking almost straight out, with the weights hanging almost straight down. This results in a great double fulcrum situation, which can even stress the ligs somewhat.
Another great thing: While in the above position, with your butt toward the edge of the chair, and the hanger sticking out, and the weights hanging straight down; you can turn the hanger to either side, a very slight twist, to further stress the sides of the septum in a dedicated fashion. The force of the weight pulling the skids into the hard plastic will keep the hanger in place, with this small turn.
Or you can scoot back in the chair, sitting up straight, with the hanger pointed down, and have a greater bend in the shaft, but a bit less double fulcrum action. Either way, it is a great stretch.