I am not sure what you are trying to say here or trying to do. Your own program
is buggy - so go fix it. As I mentioned twice already - we are on reasonable
friendly terms with the Microsoft folks, and they are happy to confirm
undocumented behaviors, and afaik from your screenshots, freetype /fontforge
matches Microsoft's rendering quite well, and your program is way off and
buggy. If you want to ask for help on debugging, ask for help properly. No,
it's evident that both are glitchy. You can't arbitrary say one
renderer but not the other does it "quite well" when both have many
errors. They are both extremely glitchy, and that's exactly the
implementation nightmare.