Well, if you got 4 procs, then concidering the proc rate of Mandau is rported by you as being 5%, 5% of 4845 is 242. 4 hits in 242 is 1.65%.
On the remaining 95% of swings (4603) you got 46 procs. Which is 1.00%.
The sample size is too small of course. But from the data you've reported it does show an increase in TH procs with higher damage strikes.
I never said SA and TA cause higher procs because of the increased damage, but that it could be a factor anyway (and could still be a factor on SA and TA. I know my SA set is stronger than my TA by a good margin, and I'm fairly certain I get more procs on SA than TA.)
From the small sample you've reported, plus anacdotal evidence from a Twatstar thief on BG I was talking to, plus the logic behind it being fairly reasonable, there seems good reason to follow the hypothesis and see if there is any real truth to it.