Also let us not forget that SD basic strategy is different for an important reason. BS is based on a neutral deck before the deal. In SD, you have 4,4 vs. dealer 6, you already have TC of +3, and you double down.
However in six deck the same hand would yield a true count of less than 1.
Not with one deck left in the shoe.
Example: Off the top of a six deck shoe (TC and RC is 0)you're dealt a pair of fives, dealer has a 10 upcard. You hit & get a six. BS and your count strategy tells you to hit again.
I would stand here because BS says to stand with a 3-card 16 vs T!I would stand here because RC>0!
Not with five decks already in the tray.