Honestly, I'd just reach out to the school and ask. Call up admissions and explain the situation. I've heard some admissions reps say that they are very strict about the word count, and another one said "don't freak out about word counts. We'll notice if you write 800 when the limit is 400, but don't stress too much" (that's a direct quote I scrawled down at a Kaplan
MBA Tour panel recently).
Another nice benefit of calling the admissions office is that you get to introduce yourself. Who knows, maybe the person who answers the phone will remember your name when the app crosses his or her desk, and you'll have banked a point of contact that shows sincere interest in the school. Probably a long shot, but it can't hurt.