I realise that Enterprise only had around 80 officers and crew but why do you suppose we never had a lieutenant commander or junior lieutenant on board? Given her position I think it's been mentioned before that Hoshi should've been junior lieutenant. Also, am I right in assuming that even in a crew of 80 with the officer to crewman ratio, should there have been more full lieutenants on board as I think all we see at least Reed as the only lieutenant on board then maybe a dozen ensigns where everyone else is a crewman?