interesting link.
The last time I looked into these things, I thought the canadian mtn guides assoc taught to do crevasse rescue this way and called it the drop c?
With the assumption of a frictionless system and a force of one unit on the pulling end, the ropeman in the drop c setup would be experiencing 2 unit of force pulling onto the anchor. With a normal z-c setup, the anchor pulley would feel a unit force of 4. When you think about the friction that gets involved with twice the unit of force pulling on it, you can see that the drop c setup makes the ropeman less of a concern than in the zc setup.