Sound like you got it … but yeah there are some weird hardcoded defaults in play, with the mousewheel. Even if you have FOV mapped to an axis … and mousewheel mapped to something else entirely.
eg. I fly with throttle bound to mousewheel as part of my HOJAM experiment… it similarly starts off at the 50% position (ie. about 75% MIL power).
And if you click the mousewheel-button, it still restores default FOV and head-position, as normal. But it also snaps the throttle back to 50% point! lol
(thankfully, press-and-hold the wheelbutton allows moving head position in 6dof … without affecting the throttle.)
It seems these mousewheel behaviors are essentially hardcoded, and changing them is not well supported (except maybe for ‘g_bMouseWheelKnobs’ in cfg).
I expect I’ll need to ditch the mousewheel-as-throttle hack, at some point, and use vJoy if I want to continue flying this way.