Well, you may even be a bit low, actually. If ten planets had the population of Earth, which isn't all that unlikely given magic and advanced technology as well as the already naturally extended lifespans of many races, then that would something along the lines of eighty billion people dead with each planet's destruction, not including the crews of the ships that were destroyed during wartime. After all, a super capitol ship would either be run by a CRAPTON of people or a bunch of AI/automatic procedures. Heck, even frigates would have pretty large crews if most of the stuff wasn't automated.