While it's a nice trick, it's a circuitous route to get to the answer, and requires considerably more stones than the number you're trying to count to. Simply laying out X stones per Y items and counting them uses no methods that the shaman's system doesn't already use, requires less stones, and doesn't require any 'good' or 'evil' silliness.

Besides, if a trick works, but it isn't understood why it works, then the users of it lose the 'ingenious' tag, methinks.