4. If you turn down your second or third choice and reapply for your first choice you had better be able to articulate why you had the board waste time looking at you for the other options when you were not serious about them.
To reiterate this point, my recruiter told me that it doesn't HELP you in any way to turn down a selection in order to reapply for primary preference, but its not a deal breaker. A GOOD letter of explanation is probably key.
I had this happen where I applied SNA/SNFO and during the wait, talked with many people about my plans and made a decision that I would have to pass on NFO if recommended for it. I was selected NFO, of course, and followed through on my plan to respectfully decline and withdraw that application so that I could reapply as SNA only. I explained my reasons for doing this in a one page letter that drew on my application essay and other points, and was selected SNA next time around.
I think my point is that you should only apply for what you really want, whether is one or multiple options. That way, you will avoid having to go through the process a second time with even more to worry you. Though you're not at a loss if you decline one selection to apply for another. others have done it...