5-7 is the span of control, could certainly be stretched to cover a full platoon for a shift so long as nothing crazy is going on. But the lieutenant isn't supervising that many officers, the lieutenant is supervising the sergeant. That's the problem, there are lieutenants effectively supervising only a couple of people. However, if, for example, a sergeant gets hung up supervising a particular situation, then someone else needs to be assigned to serve as the temporary supervisor for everyone not