If I understand this correctly, insurance is a completely different side bet on whether the dealers hole card is a ten or not. If so, it'd stand to reason that chances would only be in your favor to take the bet if there are more ten cards in the shoe than non-ten cards. But a true count of plus 3 or higher is nowhere near high enough of a count for the rest of the shoe to be more tens than non-tens. If I take a deck of cards and take out 3 positive cards, the ratio of tens to non-tends is still far below 50/50. We'd have to assume that all of the neutral cards in the deck have already been dealt in order to make an accurate judgement of whether it's advantageous to take insurance or not. Where am I going wrong in my thinking?