Ok, so I've thought of an example to explain the worry I originally had with a multi level count.
Lets say your tracking 2 half deck slugs, one of which has 3 extra ten cards, the other has 6 extra aces. The RC and therefore the TC is the same with Zen. Surely 6 aces are waaaay more valuable, and this would have shown in Hilo, where in Zen it does not.
Just a thought
Pierce