Thanks for all your feedback, everyone. (Even though it makes me anxious and slightly neurotic!)
Ultimately, my thought is that if I'm not competitive in state, I won't be competitive anywhere. I compared my stats to the schools I'm applying to, and I think I'm average to above average in all of them, not even counting work experience (in healthcare field). So, 4 it is. I think my application is pretty strong overall and I am pretty confident that if I can land an interview I can land a spot. So... fingers crossed! It just doesn't seem smart to me to spend more money than you need to for no real gain. I read stuff on the other board about kids opening new lines of credit to fund their med apps and thinking about that makes me queasy. Why would you want to take out more high-interest credit when if all goes well you'll be in school and unable to repay it? At least my worst case scenario is that I don't get in this year, I get another month and some of vacation time, a whole extra year of salary, build a bigger med school egg, and maybe take a few months off before I leave for school the next year. I don't think I'd be too broken up about it.
Anyway, thanks again for your input and good luck to everyone applying next year!