I use a similar technique.
Index finger on front of riser pointing down, other fingers curled up. This stops you from torquing the bow, and for new shooters, calms the mind because you have a finger on (or around as Denali Joe suggests) the bow, you are less worried about dropping it (some just can't get over that).
I prefer my technique because it is more comfortable to ME. Both a VERY similar, and do the same thing...just wanted to give another option IF she didn't like Joe's style.
I guess, My style lets the bow hand rotate clockwise a bit more. Thats all.