The biggest problem with ascribing hard game mechanics to military rank is that it'd be way too hard to standardize against different play styles for different play groups.
There are all sorts of things, such as the timing of sessions and how much of a time frame they cover, to how much time passes between sessions, not to mention the actual roleplaying that can't exactly be rules-codified.
I like the Alliance Contribution table, myself, which--to paraphrase the words of Captain Barbossa--is more like guidelines.