Also if you are writing a document, it's much easier to just give it a high classification to be on the safe side than try and figure out what the lowest classi

Also if you are writing a document, it's much easier to just give it a high classification to be on the safe side than try and figure out what the lowest classification it could have is. And as everybody you are working who will need to read it will have clearance anyway, it won't make it any harder for those people.