From this wording I assume its a +1 AC always.Agile Fighting (Ex)
A whirling, spinning thief-acrobat is a devilishly difficult target. Starting at 2nd level, a thief-acrobat gains a +1 dodge bonus to Armor Class. After 4th level, and when fighting defensively, or using the combat expertise or parry actions, this bonus becomes +2. This bonus is only applied if she is wearing light or no armor and is unencumbered. In addition the thief-acrobat takes no penalty to her Armor Class or on her melee attack rolls when kneeling, sitting, or prone - functionally, she is immune to being knocked down.
At lvl 4 you get another +1 AC but only when you're using FD/CE/Parry
You also get knockdown immunity.
What unclear is if the knockdown immunity also contingent on FD/CE/Parry or if it is always active. Could this be clarified?
Hopefully it isn't because it be interesting to mix in the PrC to an archer character since its dex based, but FD/CE/Parry can't be used with ranged weapons.
