I have the same thing on my PT-40. If built per the plans, the wings have quite a bit of twist designed into them (washout). The washout (tip twisted downward) aids in stall resistance. Even if the aileron is perfectly straight, it will not seem to be parallel to the trailing edge of the wing. Just fly it man, the PT-40 is a gentle plane that is very capable of basic aerobatics. Inverted flight can be tough, but is doable.

Good Luck!