Thanks for snitching on your own job, it's appreciated! Both things you spotted are how the original pre-BB game shipped. Final Attack: Bow really did go to Master Level 30 back then (the 20-level cap came later). The odd 50% on the Level 29 line is a typo in the original game's own skill text: every other Final Attack reads 58% at Level 29. The game doesn't use that text for the actual roll; it uses the real skill data, so Level 29 procs at 58% and Level 30 at 60%. We're keeping the original text as it was.

Update: Mark decided to fix the text. Final Attack: Bow's Level 29 line now says 58%, matching the actual proc rate (Level 30 is 60%). The skill's real behaviour didn't change, only the description. To re-test: open your skill window and hover Final Attack: Bow's next-level info.