OK. I found it myself. Roadracing World, March, 3003. Here is the point. THe way the new suspension is designed, the force actually pulls down on the bottom of the frame spars. This is a completely different effect than an upward force at the cross member.
I do not think your point about where the force enters the frame is correct. If you load those vertical spars with an equal upward force anywhere along their length, the result will be the same. Because the frame is supporting the mass equally at every point along that vertical axis, the effect of pushing enengy into the spars from the same direction is identical, I believe.
But if the force were reversed, into a pulling rather than pushing motion, that would be, and apparently is, completely different.