What I ment was that the observer's firing platform is moving laterally in relation to the oncoming target making the shot a deflected shot for the gunner/observer. I think that's the way that was interperted in the orig. boardgame rules(?) We might drop a note to Phil Hall for his perspective on the issue.
If the rules were interperted the way I think you are reading them;any attack coming from any hex within the observer's arc of fire would be a "no deflection shot" for the observer. That would make the obsv. VERY deadly to enemy engines creating perhaps an inordinant number of gliders. I'm pretty sure the designer's intent was that only direct nose on tail and tail on nose shots were to be at 'no deflection'.

Damage.

If an aircraft is fired upon from directly to its front, all tail hits become engine hits.