Some guy I know kept implying that Full Break's defense-down effect actually worked all the time, so I wanted to see whether there was a ninja-update to it and I also wanted to verify the duration of debuffs (I did earlier but I came to the wrong conclusion based on this latest checking). Tested on Qufim crabs. I didn't see any corroboration anywhere, not even JP wikis or Gobli.
It seems that the debuff duration can be either 90/180/360 s at 100/200/300 TP or 180/360/720 s at 100/200/300 TP with the appropriate piecewise linear functionalization. I consider 90/180/360 to represent a "resisted" state. It would be interesting to know if baseline debuff accuracy is terrible in general and if it can be increased, but not really worth checking.
Data table:
Spoiler: show