I discovered a difference between playing on JP audio vs playing on English audio, and that's primarily with the Crystal Awakening cutscenes that can't be skipped, both text and scenes.

The game is 30 fps. Doing any% is about 10 seconds faster with JP than English audio, or 310 frames. For true ending, it's about 50 seconds faster with JP audio than English, or 1520 frames.

The time save is minimal, but if you're looking to save frames, there you go.