Looking around at the list you're right Peter. There are similar issues for a number of controls. Elevator trim was the one I always get stuck on.
Using 3.601 and FS9.1 ....
Elev Up
Elev Down
Elevator Up
Elevator Down
Elevator Set
Elevator Trim Set
Also
Airelon Right
Airelon Left
Airelons Right
Airelons Left
Spoiler Dec
Spoiler Inc
Spoilers Arm Off
Spoilers Arm On
Spoilers Arm Set
Spoilers Arm Toggle
Spoilers Set
Seeing now that you are extracting the names from a DLL helps a bit. In the above list I can manage to figure out most of these fairly easily. It's the similarity in naming that causes confusion, plural vs singular.
Double-checking I note well that you did document the axis' labels as part of the section on assignments for yoke and pedals. That did help me a lot in my efforts. Any hope for more descriptions for other parts?
WRT "set" commands. I knew they'd have to take a value, but not that they were related to "axis" commands. Had thought the "set" was for some programmatic control and "axis" for binding to a input device.
As always, very appreciative of the work you do!!