moving along the elbow plane line on the BS

[noproblemos]

I was looking at some pro swings from the down-the-line view. I drew a line from the ball through the rear elbow.

I noticed that many pros get the clubhead and shaft onto that plane soon after their swing starts.

After their trailing elbow continues to bend (and as the backswing proceeds to the top of the backswing), it seems that the clubhead and shaft shifts above that line drawn through the elbow.

Is there anything wrong with keeping the clubhead and shaft on that "elbow plane" instead of moving above it? Or would this mean that the elbow and every thing is moving too far "in" and not enough "up"?

Thanks,