[Martee]

The Head-Centered is --ideally -- Centered between the Feet. In addition to the sensory advantage you have mentioned, it also offers an immediate visual confirmation of compliance with the Pivot Center requirement. It is an absolute, just as is the Straight Plane Line and the Flat Left Wrist and the Parallel to the Plane Line Clubshaft (when it is Parallel to the ground).

It also serves to Center other mission-critical Components -- the Shoulders, for example -- in preparation for their Uncompensated return to Impact.

Despite these advantages, the player can choose to locate that Head Center behind or in front of the Visual Center.

Or choose another Center altogether.

The question then becomes...

And you are very right to ask here, Bob...

Why do so?

This might be one of the best posts regarding the why's behind a stationary head. Most posts really just regurgitate the book.

I think if you discount the sensory advantage then you can make a solid case of another static position/reference point.

I think either position still requires a stationary point of reference at or above the shoulders rotation arount point, a dynamic point would complicate and require timing to make a solid consistent stroke. Probably not repeatable for most, especially with age.