Keep your shirts on, everybody.
What you are looking at is a composition-dependent index for the play. As it turns out, the 6 acts as a high card, a very high card for the play 16 vs. 10. If the next card is a 6 it will bust you and you don't want a hit, and if the dealers hole card is a 6 the dealer is in trouble and you don't want a hit.
The 6 is so powerful a card in the 16 vs.10 decision that it can indeed throw the decision off in a SD game, especially in the High-Low count where you have already counted it is a low card when you have 10,6. If your hand was 6,6,4 the count to stand would be even higher.
We see the same effect with 14 vs. 10; with 10,4 you would definitely hit but with 7,7 you would stand, because your chances of getting your 21 have been so depleted you are better off letting the dealer go first. There is also a lower chance the dealer will make his hand with two 7's dealt out, and that is part of the decision too.