My instincts tell me to never take a 5th card.
In this case the count is 0 in a 4/6/8 deck game and my total is 12 to 16, I haven't drawn a 10 yet. My calculations say that I have a less than 3% chance of dodging that bullet ( 4/13 to the 5th power = .00275 ). Drawing 5 cards out of a full suit of cards and not catching a 10 is about 1 in 361, seem like long odds to me. This also doesn't take into account the other cards that will bust the hand depending on exactly what my total is.
It seems sound but without proof it's just a hunch and I'm not comfortable with that. My calculations could very well be dead wrong. But if correct, I suspect that this is closely related to the 5 Card Charlie.
Any help shedding some light on this would be greatly appreciated.