I have a very outdated 2007 edition and that did well enough for me. Like one of the people above said, you are missing quite a few questions, but for me spending nearly a 120 more for an extra few hundred questions didn't seem like a great idea. Something like Achiever or Top Score will give you 2000+ or 1000+ questions for $140 and $60 respectively and they cover all the DAT areas.
Honestly, Destroyer is good for material review, but for a more DAT experience pick up achiever instead. If you are weak on the sciences though, Destroyer is the best prep tool. If you want to concentrate on the DAT as a whole Destroyer is not even in contention since it doesn't consider RC or PAT, both of which can give people major problems.