In a Two Deck S17, DAS, DOA, 75%
Using Uston APC with separate count of Aces in a 2 Decks, S17,DAS, DOA, 68%-75% pen.
Negative counts: 44.669%
Zero : 15.755%
Positive counts: 39.581%
You can lose 20 in a row on positive counts alone but you can also win 20 in a row.
You can also can win 20 in a row in negative counts or lose 20 in a row on negative. The count make no difference of how many in a row hands you will lose. If you construct a positive deck (adding extra Tens and removing 5s) to generate a artificially positive deck and play $$ into that deck. You still will lose more hands then win but in this instance you will make money. (48% losers and about 44% wins) Further more, you still can lose 20 in a row on +10 counts alone in a long BJ life (over a million or so hands)
Don't worry to much about this. Your advantage in positive counts is from betting more and getting 3:2 on BJ and probably a little extra on Double Downs. That's all it is.
Now, listen to me! ..,the EV on positive counts is not everything what you should look for in this game. If EV were sacred, then the correct thing to do whenever you have an edge is to bet your entire bank (not just what's in your pocket) in order to maximize your expected net worth after the bet is resolved. This is obviously a bad idea, because you will have zero net worth just as soon as you lose a bet. It isn't a matter of wimping out or having an emotional reaction to a large bet, it is a matter of noticing that there is a very real downside to maximizing EV.
Maximizing expectation is a strategy which complete ignores risk.
I've never met anyone who truly believed that expectation was everything, and who would prove it by betting their entire net worth on a single outcome even in a very positive count. If your bets are too large, then you are very likely to end up broke even though you have an advantage. This is the PARADOX of BJ, but it is true. It takes more than positive EV to assure with high probability that you come out ahead. You must also moderate your bet size and be patient. The phrase "money management" has a bad reputation that is undeserved. But, the reality is that it is important to control your bank. Scam progression systems are wrong when they focus exclusively on money management, because money management does not change the house edge. The truth is that you need both a positive EV and careful money management in the form of bet sizing that is carefully coordination with the VARIANCE of different plays (i.e. Splitting and mostly the Doubling Downs where the variance can quadruple for some plays vs. just taking one or two Hit cards instead) in order to have a high probability of coming out with more chips that you start with.
Puiu