The window is short and everyone wants it
A low-stock period is also when a site schedules its maintenance, its racking checks, its line remarking and any building work it has deferred. The window is a fortnight at most and several parties want access to the same floor. A cleaning attendance that is requested once the window opens will be fitted around everybody else or missed entirely. Racking inspections in particular need the bays empty and take priority.
Booking it months ahead, at the same time the site plans its other work, puts cleaning into the sequence rather than at the end of it. It also allows the order to be sensible: cleaning after the trades have finished rather than before, so the result survives. That sequencing conversation is worth having with the site manager rather than assuming a slot. It also gives the crew a realistic idea of how much floor will actually be available.
