[Gregstrom]

To tie this in with KO's post above:

An 'attack action' consists of all your attacks (as listed when you right-click on a unit's attack score?), and subtracts your BAP from your Action Points for the turn). I don't think it's possible to attack with less than your full number of attacks.

The whole 'extra attack' bit really means that when your CAP value is higher than your BAP, you may have AP left after making an 'attack action'. Those can then be used to attack again (or move, or whatever).

There's a good example of AP use on page 74 of the manual.

I actually find it confusing to think in terms of Quickness granting an action rather than extra AP (a legacy of my days spent playing Laser Squad, perhaps).

Also, thinking in terms of AP rather than actions may help if you need to factor in Haste as well as Quickness.

I'm guessing here, but does casting a spell set CAP to zero instead of subtracting BAP from CAP?