Question about the Autopilot code

I tried to ask this a month ago and trying again from a different angle. The autopilot is not working properly when trying to run the simulator on high rate (X8, X16). Since some people here are working with the code (flybywire for example) - do you know where this magical update every 100milisec or so happens? Maybe someone can point me to the right place to I can try change something that might make it work?