In addition in my day as an infantryman the 2IC of a section was also the admin man. It was he who looked after the admin, managing the ammo state, making sure the men were being fed and watered, sentry rosters were made out etc. All this was done to enable the Sect Commander to get on with attending O Groups, and writing his patrol orders etc. of course this does not mean that the Section Commander is not personally responsible for all that happens in his section.
The same thing would also happen at the platoon level where the Pl Sgt did the same thing on a platoon wide basis enabling the Pl Comd to get on with the preparation for battle in terms of orders etc.
If you are any good as a 2IC your Section Commander should be able to rely on you to get the Section organised and ready for the next task without his direct supervision. Thus whenever he appears with the next set of orders, the section is as ready as possible and not faffing about trying to complete its basic personal admin.