I am a volunteer, and the developers are either busy or unavailable. Sorry about that.
As far as OnAir goes, I find them relying on the physical position of the cockpit controls of default systems to be rather dubious, to be honest. Firstly, maybe not every aircraft is using the default flap control, and secondly, that doesn't correspond to the actual position of the flaps on the wing, which seems to be what they should actually be caring about.
I think a more versatile and reliable solution would be for OnAir to allow the source of these signals to be configurable on a per-addon basis. I believe there are DataRefs in the Challenger that could be used, but copying these back to the X-Plane defaults wouldn't be priority at the moment. I can look at passing the suggestion onto the developer, but to be frank, you'd be better off looking for another way to make this work (custom Lua script, etc.).
Thanks.