I don't question that a person can have the mental ability to track multiple tables. But the speed and timing of the game, ignoring the visual issues, make it impossible, to me, to see each and every card. If cards are dealt at exactly the same time, and players are hitting, I don't see how you can actually see every card. So even if you can somehow see both tables, I just don't see how the count can be accurate. I also question that missed cards just go towards the penetration. If you missed 6 faces and still thought you had a positive count good luck.