Good question. It does seem like double-booking and in a bad way, doesn't it? I went the other direction and replaced the -2 DM with the range DMs. Keeps the DMs to a single mechanism, streamlining combat.
I hope one of us is correct. Otherwise, as you pointed out, it makes pulse lasers pretty useless despite the damage they provide. Even 10d6 damage = 0 if the weapon doesn't hit a target most of the time.