My friend and I tested Level 5 Provoke ("80%" stun rate) 60 times. It succeeded 19 out of 60 times ; this ratio comes to 31.6% success rate, maintaining roughly a 33% success rate throughout the entire test. There was very little fluctuation.
Investing our curiosity even further, we decided to test Level 1 Provoke ("60%" stun rate) as well. We ran another 60 tests at Level 1, and it succeeded 16 out of 60 times; this ratio comes to 26.7%. This percent is so close to the first one that one can only assume the difference is simply due to 60 being a small test group.
Conclusion: Provoke's success rate is roughly 1 out of 3, regardless of its skill Level, and the description is false,
Edited by Bustincaps, 16 February 2016 - 10:52 PM.