Using the default code and values I noticed the hit chance was extremely high until weapon falloff. I only tested a few levels, but the hit chance was generally around 62% afterwards (down from 93-96%~). You had to have modified something in the code or database that screwed something up. I'd revert all of your changes.
Code:
[03-17-2016 :: 20:50:12] [Attack] Chance to hit after weapon falloff calc (defense) 93.75
This right here is the issue.