I have a copy of the books as well.
the system is kinda weird for point buy, 16 is the stat that they want you to go for as far as I can tell.
You start with 5 10s and an 8. 8-13 costs 1 point. 14, 15, 16 cost 2 points, 17 costs 3, and 18 costs 4. You get 22 points.
Basically you pay the bonus you are getting with that point. Except at 16 where you just pay one less then the rest of their pricing scheme for no reason, making it apparent that they feel 16 is a good break point. you can go to 18, but it hurts.
Now I have a question for DMs out there. Would you stick with 22? or would you raise it a little (like everyone did in 3.5 from 25-28/32). I like 25 a lot, that has a fair amount of variance. you can have an 18, 16, 12. 18, 14, 12, 12. You basically can't get an 18 and make an effective character with 22, except a wizard, even then it's risky as you'll have at least 1 really weak defense (fort).