He really has two choices for what he is suggesting, unless he is asking for some extremely complex and situational piece of code. He either wants both to suffer damage in a collision, which he said no to, or wants the collision to only apply damage if both FEs detected a collision.
The problem with the second method is that it leads to planes with non-explosive rounds flying through their target aircraft, guns blazing. It is very easy to hit from 10ft. Bombers in particular would suffer for it.