Totally agree , maybe I mis communicated. I don't endorse the flick . Common though it is. However I do think that its the flat right hand that is swivelled on to plane in finish swivel, ideally. Thats the alignment or wrist condition for the free flowing flail.
Just pointing out that he's gone from one extreme to another in regard to the flat left wrist and I don't believe he's got it quite right yet. Not then , not now
Learning to Roll a Flat Left Wrist through impact is still the first train out of Hackersville. Delivery Line Roll Prep.