Ahah - I'll answer my own post, since Horizon Hobbies responded, stating that what's in their manual is "a misprint", and that it was "printed directly backwards".
ORIGINAL: Tim Green
Can anyone explain why the H9 J3 Cub manual shows reverse aileron differential for the control throws?
Typically, less down travel than up is recommended for ailerons on non-symetrical wings, in order to counteract drag induced yaw. But as you can see, they're recommending more down travel than up, not less.
From the H9 J3 Cub Manual
Aileron Control Throws
Low Rate
3/8" (8º) Up 1/2" (9º) Down
High Rate
7/8" (21º) Up 11/16" (22º) Down