There is actually somewhat of a 'divide' or 'spectrum' amoung maxfax docs. On one end you have docs like Gunson who want to get not only the bite right but also the form and function of the FACE right with that. On the other end, or somewhere near that part of the spectrum, you get types like your guy who stop at getting the bite right.
Also, with your guy, you have the 'double damning' of his being the head of a teaching hospital where a lot of the work is given to the residents who are just learning. I mean, who knows? When you're allocating some surgery to residents, depending on where they are on the learning curve, you don't want to give them TOO MUCH to do. Like maybe they need to start (and stop) with just getting the bite right.
The good news is that they eventually got the bite right and you have a VIRGIN chin that was not touched by a resident. So, now your free to pursue an isolated (sliding) genio to reduce chin strain and make it easier for you to close your lips (address the residual lip incompetence).