The proper amount of Knee Bend is determined at Impact Fix and 10-16-C Right Anchor (flat pre-impact motion)is the Knee Action component selected for 12-1/2.
There doesn't seem to be any indication of the benefits or disadvantages of the other classifications.
Under what conditions would a player select one of the other Knee Action classifications? For example, when would one want maximum slant at each end of the stroke (A); a flatter turn through impact and follow through (B); or a very flat turn throughout (D)? Or, would these be compensations to be avoided?