I see I have misunderstood it then. I still think though, that misses should be a thig. It could work like interception, like remove movement times d6 from incoming damage. Perhaps not needed, but smehow it just feels good, when a whole fleet is firing at you, and they just can't hit. Then again, working with hundreds of ships, this could get iresome, and i am no one to judge your decision of not putting it in.
Also very nice work, it is a hell of a lot simpler, than the old one, yet it works identically well, if not better due to not having to calculate a lot.