When you are fixing the golfer who swings TOO FAR TO THE RIGHt and has TOO CLOSED A CLUBFACE (The "so-called" hooker), if you just fixed his face, the under the palne move would produce a WEAKER shot than the normal "problem" shot he showed up with.
The Slicer who SWINGS TOO FAR TO THE RIGHT and has a CLUBFACE THAT IS TOO OPEN, will hit a longer, stronger shot after fixing the face.
That's only one reason.
The next reason is that when you are getting the "Hooker" to not: lean away so much, not tilt so much without rotation, etc., that golfer is often most shocked by where the ball goes with JUST a fixed pivot and path.
That is becuase of a bunch of things, but mainly becuase of—what I call—reaction HINGE action.
There are many more reasons, some I'd like to keep to myself

, but trust me, this approach: "fixing the clubface FIRST in NSA but fixing PATH/PIVOT first in NHA" is mainly becuase, after 25 years of fighting my way to where I am today,
It works better.