Hi Mattew
Another idea sprung to mind....
Your hysteresis value H seems to be an absolute. I think it would work better if it was a percentage. With large meshes, the further away you are from the originator, the smaller TQ is, because of the link penalty. Thus with an absolute value of H, the relative quality of the link has to change a lot more when you are many hops away, than if you are near by.
Andrew