I think some of the information in your theory comes from this TWU article http://twu.tennis-warehouse.com/lear.../kickserve.php
that supports more spin being generated if you strike the top of the ball. I have also seen other web instruction that you must get the racket head in front of the wrist to hit a good kick serve too and this supports your theory also.
I have an OK kick serve - not great - but I target the bottom inside and swing up to the top outside at almost a 45 degree angle thru the ball. I do try to keep the shoulders turn, swing more at the side fence and get the racket head through the ball - racket head slightly in front of wrist.
In reality, the racket probably does brush across the top of the ball as you indicate. Maybe contact the bottom or center but brushes across the top before the ball leaves the strings.