Gray, It is called underslinging, and as the disc tilts, it adjusts the length of the rotor blade by an amount to reduce the "ballerina" effect with conservation of angular momentum. Tilt the (coned) disc forward, and the rear blade apparently is shorter and the front is longer, causing problems with one trying to speed up and the other trying to slow down. Causes stresses in the head. So, the underslinging pokes the rear blade out a bit and pulls the front one in a bit.
A very basic explanation, but maybe of use to you.