Hummingbird

Hi all, I started playing A:EftP last night and fought 4 battles...still in the very early in the game. I read in the manual that's included in the game that it takes 9 AP to attack, but my characters start with 8 AP at the start of combat...also I can attack even if I have 1 AP left? Also, if I'm next to an enemy and I attack without moving before...all of my AP depletes and I can't go away. I'm confused...what's going on? The way that AP is working in combat now doesn't match with how it's described in the in-game manual. Maybe I mis-read something? Any clarification would be helpful, thanks.