I would say the CO deserves it. But the Navy normally uses O5 to command ships of similar crew size. Very rarely, even O4... it all depends on what exactly the

I would say the CO deserves it. But the Navy normally uses O5 to command ships of similar crew size. Very rarely, even O4... it all depends on what exactly the ship is, and what the expected mission set of that ship is. Obviously the Navy wouldn't slot a random O4 into minesweeper command even though it's a small ship, so you're really talking about a "better than average" O4 even for those, it just reflects back to how scope of responsibility can change things even for the Navy.