Maybe your expectations are too high?
If you play-all with that spread, assuming a penetration of 4.5/6, your expected value is 0.43% and your SCORE is 8.33 (according to www.bjstats.com). This means that if you have a $10,000 bankroll and are making optimal bets, you can expect to make $8.33/hour. For your spread, expect to make about $5/hour with a relatively high variance.
If you wong-in/wong-out, you increase your expected value while lowering your variance, resulting in a much higher SCORE. However, don't expect to win much more than $10/hour with a $10-$50 spread.
It isn't HiOptI that's the problem, although it would be a lot better to use HiLo for shoe games. Not only do you get slightly better results, you don't have to sidecount aces. HiOptI is best suited for single decks games, assuming you learn a lot of indices.