Similarly, sometimes people claim Virtue stone weapons are 55%. They might genuinely have a different DA rate, or it might just be a test with an insufficient sample size. It's probably the latter, and until it's confirmed otherwise I'm assuming that all "Occasional attacks twice" weapons are 50%. I don't know about the Amoods (I'd assume they must be higher) or the Campaign GA.
Triple Attacking weapons (Ridill, Soboro, etc.) are generally assumed to be 30/50/20 before DA is applied.
Mercurial Sword is something like 20:40:33:6
Mercurial Pole's distribution unknown, but it is confirmed to hit up to 5 times in one attack round.
K-club is supposedly 5:15:25:25:15:10:3:2
It almost looks like it's a shifted distribution that they just expand based on the maximum number of possible attacks.
XI Wiki


