oh yeah I do all that stuff, it's just my personal experience that when I've powdered decks right away (usually because... I just can't wait! hehe), then after a short while they seem to lose all the powder since it doesn't have as good as ability to 'stick' to the finish, as it would if the finish was worn down.
however since your method also includes a re=application after the finish is worn down a bit, it's probably "6 of one, half a dozen of the other". I usually just try to go ahead and practice with the slippery, new condition deck , for the exact reason which you describe in your above post... what if someone hands you a new deck?
actually LOL I would prefer if someone handed me their new deck rather than their totally f'd up deck that they've been playing cards with for a while. at least then you could do a dam Pharoh weave with it. I brought a deck of palmettos to a hold em game and the chick next to me shuffled them with such enthusiasm that the deck is totally hashed beyond porper repair right now. should've brought some dam bees or something.