Re: data department change in chain of command
^ Why? As has been pointed out here in this thread, the real life U.S.S. Enterprise of the United States Navy has two officers of Captain rank serving on board. Why should it be any different within Starfleet?
Because TV executives think general audiences are too stupid to wrap their minds around such a concept. Same reason we got Romulans with ridges.
"If I hadn't tried, the cost would have been my soul." - Admiral James T. Kirk, Star Trek III: The Search for Spock