I think there must be some AI in the gunnery too. That not directly controlled by the player. For example, I'm in the tail gunner position. I shoot at a fighter. It's been a while so I may be wrong but the gunners in the other planes shoot too. Their aim cannot be controlled directly by mine or just the fact they aren't sitting exactly where I am means they will never hit where I do. I think it likely an AI is "choosing" to aim at the target I am aimed at.