Pincer and Berserk

[Ridgeway]

I have Pincer and Berserk both at 100%. However, sometimes they do not work properly. At 100% Berserk should go off every time. Pincer should never say I crossed up my weapons and failed. I thought that was the whole point in taking skills to 100%. If there is something I am missing, please let me know. Otherwise, can you take a look at these 2 skills, and see why I still fail them sometimes, even though Im at 100%. Also, Im not talking about missing. Missing I understand. I don't understand failing to do a 100% skill. Thanks.