[O.B.Left]

Hmmm. Im thinking not necessarily. Manipulation or steering aside you could get to level on any plane angle Id imagine. Although as you get flatter you do approach an angle that is heel down in terms of the clubs lie angle. The vj trolio lob shot where you swing way below the hands plane requires the clubface to be opened way up to avoid the heel down problem. But you can still get to level with the left wrist. Try swinging on you knees to see what I mean.