OK, keys assignments are inverse for Spit. Period.
But the lever animation in cockpit are correctly, lever ahead fine pitch (max rev). I think that in first release of game are in wrong way...
And, since different planes and aircraft system use the same (key) commands, if the game have "correct" keys operation for Spit, have inverted operation in Bf 109...
The problem it's all in core code - in game concept/design, Luthier/MG aren't not able to fix this (and more). I dont expect that TF fix it someday.
It's all "Typically CloD": unfinished, bugged, confuse...

What we do now is matter to learn and adapt.
Another examples: when you hit the key (O) to
close Spit cockpit side door - that are the same key used to close canopy - you see in HUD:
Hit to close side door:
Hatch door: Open <<< ??? And see the side door moved to closed position...
And when hit again to close canopy, see:
Hatch door: Closed >>> And see canopy moved to closed position...
Or engage WEP in 109/110 and see in HUD: Afterburner:ON...
Or drop a single bomb from internal bomb bay of Ju-88 and door (hand crank ("+", "-") controlled) closed without command...
Sokol1