question on I 18?

[Midwestern]

looking at the Indices i'm a little confused by the logic on 16

if the TC is anything higher than 0 , we stand on 16 v 0.
ok makes sense. 16 is almost 17, a positive count we want to stand, especially vs a 10.

so why do we wait until TC +4 to stand on 16 v 9?

kinda seems like overkill, no?

 

[neversplit5s]

The reason why 16 vs. 10 has a lower index than 16 vs. 9 (which is lower than 16 vs. 8, and lower than 16 vs. 7) is because as the upcards go up the most likely dealer's hand goes up (from 17 with a 7 to 20 with a 10, which the effect becomes more magnified when the deck or shoe is 10-heavy). As you become less likely to eke out a win upon pulling a non-bust card with a higher dealer upcard, it tilts the better move towards standing and hoping for a dealer bust.