I only said that 144° effective shutter angle is possible, not that you can achieve it by deleting 4/5 frames (which does give you effective 72° shutter angle).

I only said that 144° effective shutter angle is possible, not that you can achieve it by deleting 4/5 frames (which does give you effective 72° shutter angle). You actually need to delete 3/5 and blend 2/5 (and the 360° shutter angle of the 120fps source needs to be accurate enough that you don't see the join).