The Chalier jack conundrum is most likely because that card is more worn than the rest, crimped a little or from a different deck
Look at the side of the deck and you'll probably notice one card darker than the rest - I used that as a 'key card' technique for aaages... I've never tipped it before now either....Ah well, someone else probably published it hundreds of years ago
D.
Yeah man, it's called the DDP (Dirty Deck Principal) lol. I just found out about it yesterday.