I'm a swash. I pulled the numbers from Kor-Sha, less OK. Reason I was studying them so much is because I was getting my ass handed to me by the assassin.
Sample size:
Swash:
Pierce/Slash - 688 crits out of 978 hits (70%)
CAs - 1309 crits out of 3174 hits (41%)
Assassin:
Pierce/Slash - 732 crits out of 1077 hits (67%)
CAs - 2627 crits out of 4079 hits (64%)
I had a dirge w/o DA, he had an Illy.

We have similar weapons. I sit at 73% crit, he's at 58% +15% when his weap procs.
I'd believe that ACT's picking it up wrong, except that his numbers add up right. I must be doing something wrong.. I just can't figure out what...