I am a student naval flight officer - 1375.
The security manager will have you sit at a computer that asks numerous questions about your background. I think the information is then sent off to a specific office where they process your data. At least that is what the Chief did when I did it. I don’t know all of the details as to what happens with that area of the package. All I remember doing was answering those questions and eventually having the Chief sign off on that piece of paper from the OCS Word document that is included with the package.
As far as the package is concerned, the selection board will not view sending more as being overkill. I'm not talking about sending them stuff like lab results for your blood, a note from your 2nd grade teacher, you dog's AKC registration, and other frivolous items unless they are specifically asked for. What I am referring to are the items I listed in my outline, especially if you are applying for an aviation designator. This is from my own personal experience. And, as I stated, your experiences may vary from my own.
I received emails from the OCS package department that stated I was missing A, B, and C from my own package, so I had to get those documents and send them their way, which only took more time to get my package accepted. If you are nearing the age limit for a specific program, be thorough and leave nothing to chance.
If you put something in your package that they do not require, it will merely be disregarded. But to not include everything they need will cost you more time in waiting to hear back from them to see if you are accepted or not.
Send more and be thorough, but send what is relevant to the program that you are applying for. The board may perceive your ability to follow directions as lacking if you do not fill out the required paperwork correctly the first time (thus you should have at least 3 other people look over your package from A to Z), but if you include more than they require they will look at it as though you are thorough. This is a case where more can be better than not having enough.
Also, I don't think they require that microfiche now. I put my package together back in May of 2001. I remember someone saying that I didn't have to include my microfiche, but that if I did it would save the OCS package department some time in getting specific information. I was racing against the age clock to be eligible for this program, so I included the microfiche to save them as much time as possible.