N00b question… Always on AA guns (2nd Edition to be specific)

[FizzIII]

Okay.  I’ve ran across this term in TripleA and seen it around a couple of places, but I haven’t found a good definition of it yet.  Can someone explain this to me?  I thought it was a house rule that people use, if not please forgive me.  I used Triple A and started a new game and added a dozen or so fighters to Karelia to attack Germany with the option on and off, but I didn’t really see a difference in behavior.  I was thinking that meant they attacked at the beginning of every round, but is that not the case?

Thanks,
FizzIII

[FizzIII]

Perhaps thinking about this long enough helped… Always on would mean the AA fires during all movement, not just combat movement?