I think the reason it appears that Rick creeps forward on some of his shots is the same reason I was doing it after attending his class: because of his nose anchor, the draw becomes a two-step process. You draw the bow, then you rotate your head and place your nose behind the cock feather. If you drew the arrow a little too far back to do that, you have to let the arrow forward a bit so your nose will fit. Then, during the two second pause that Rick emphasizes is of critical importance to his method, you regain the back tension that you lost when you positioned your nose. The method clearly works, and the best example of that is Rick himself.
However, a valid question is whether there is a better way of doing it. When I attended Rod Jenkins's class, after attending Rick's class, Rod noticed me doing the same thing Terry noticed in his post above. He had me change Rick's method slightly, so that I tilt my head as I draw the bow, and draw back directly to my nose, rather than drawing back and then positioning my nose. The result was that my arrow didn't creep forward, and I never lost back tension. I think I'm shooting better for making the slight change, but that's just me, and I'm not in the same class as Rick or Rod is.
I've always thought the reason Rick's hand flops is because he keeps it very relaxed during his draw. That and the fact that it happens more often when he is shooting heavier poundage bows. I've seen other people shoot who were trained by Rick, including some who two-step the draw, as I describe above, and I haven't seen other people's hands flop like that.