[O.B.Left]

Know what you mean about Hogan and the Right Arm being on plane at address. But in that photo of him above, you'll notice a shag boy out in the distance , right at the top of the Shaft Plane line you drew. That is his target. As such the camera is set up square to his foot line but his foot line, stance line is closed! Dramatically. So the camera is not square to his Plane Line or the flight of his ball.
This exaggerates the off the shaft plane look of his right arm. Not saying that is an Elbow Plane it isnt. But he isnt as far off it as he looks here.