Answer
21&counting is right in that AOII is in Bryce Carlson's Blackjack For Blood.
Hi-Opt II is a different count created by Lance Humble. I'm not exactly sure were you can find this system.
If you look at the left side of your screen and scroll towards the bottom, you'll find BJ Glossary which can tell you a little more about the point values for each count.
I have heard that Hi-Opt II performs slightly better than AOII. These systems are compared in Blackjack Attack Playing the Pros Way by Don Schlesinger.
Hope this helps,
Dominic