re: Poker & HUD stats,
Well inference can be drawn from the fact that the higher your AF the more likely you are to bluff. But that's not to say someone with an AF of 0.5, doesn't bluff.
Basically afaik, AF if the ratio of you betting/raising to you calling. So if you have an AF of +5 then you very rarely call, whereas someone with an AF of 1 or less will call more often than not.
Now to correlate the high AF with someone who you think bluffs a lot, you really have to look at their main stats as a whole. For example, someone who has stats of 6/4/4, certainly wont be bluffing
a great deal, as he only raises 4% of his hands spread across all positions, so he's likely to have a decent hand most of the time.
Whereas a player who has stats of 25/20/5, you can guarantee he's bluffing/semibluffing a certain amount of the time. That doesn't mean all the time though.
Don't forget AF is total AF across all streets afaik.