why tfm mode 5 creates jerkiness?

[OvejaNegra]

According to TFM readme:
3-way matching
+ trying the 4th/5th matches if all 3 of the original matches are detected as combed
(option 5) is the most risky in terms of creating jerkiness, but will almost always
find a good frame if there is one.

I dont understand: Mode 0 follows the normal match order (p/c). But in my experience, with bad footage mode 5 most of the time finds the good matches (and mode 0 fails on many frames). If i apply Tdecimate after TFm (as the normal operation) and tdecimate removes the duplicated frames of the cycles, then why the readme says that?
Arent the bad matches (flaged as interlaced and then deinterlaced with the internal tfm deinterlacers or with clip2) more risky of being detected as non duplicated and then the whole cycle detected as video AND then create real jerkiness (for example a FILM panning scene detected as VIDEO and then the duplicated frames stay there and the scene is jerky).

Or the documentation is wrong?
Or im missing something?

(I always create 2pass mkv with timecode in case that matters)

Sorry for my english.