HD focus PVP

i happen to have a HD focus, 150 fire, focus SA...
and was wondering if it's worth it to pvp augment it on top of that?
(regular augment is just some +P.attack, couldn't get + crit for some reason)

i mean it claims to occasionally add damage to a hit...
but how often, and does it do it to critical damage as well?
or only on critical damage?

i mean if the damage increase on a whole is better, i say worth it.
but if it's rare... then maybe not so much.

I had this on my weapon for months, but never saw it do anything.
Took it off to change augment and haven't bothered to pvp it again.
Anyone else have PVPed two-handed sword and actually seen it work?

well, i guess nobody uses the pvp augment...
so i'll save the 2 million adena, and 12k fame for something else.