Rather than "misdirection", perhaps a more useful concept in this context is "offbeat". It's surprising, but with a well-constructed offbeat, it doesn't matter if people are looking right at the deck because they still won't see anything. They won't be expecting to see anything, so they don't. We're conditioned to expect actions to take place at a moment of high tension: a runner "gets set" before sprinting, a fist is drawn back before a punch is delivered, etc. It's what you could call "the coiled spring effect". I would bet good money that, at the moment, you're building tension at the moment of your top change, which is why people are spotting it. If you learn to time your move at a moment of relaxation, you can be confident that no-one will see it or, having seen it, won't place any importance on it. A good way to practice in front of the mirror is to drop your shoulders, look at your reflection in the eyes and smile. On the smile, perform the top change. This will train you to associate a relaxed state with the performance of the move. In performance, maybe rather than just smiling, you might want to say something ("Well, I suppose that just proves I'm human after all!" if you're changing a wrong card for the right card, for example). I hope that makes sense.