[Rain Man]

Yeah, "hitting" is different than "damaging." Both planes will have their attacks disrupted, but it'll be more for a damaged attacker. The damaged attacker will also break off his attack after the run, while a "hit" fighter will possibly circle and attack again. It's your call about whether this is a big enough difference to document.

As for damage to the B-17, that's a toughie since there are so many things that can happen. A simple approach would be to just note the number of hits, which would be simple since you could just add them up from the mission history. Of course, four superficial wing hits is a lot different than four hits that each take out an engine. Depending on how much time you wanted to invest, you could summarize the number of hits and "significant damage" that impacted the plane's performance or something.