BDIONU
I don`t see what a DD&C has to do with anything. I have done them before with 3 people on nights.
From what i understand is that by only having 3 on nights then you are relying on the sectors being bandboxed by 11pm (when the 1500-2300 people go home) and then not splitting till 5.30am when the 1st morning person comes in. By doing away with the 5.30am shift & having 4 on nights then it gives you the freedom to keep the sectors split late in the evening & also gives the capacity to split early in the morning which with the increasing traffic in the summer then it is needed some days depending on the eastbound track structure.