Approval has to be written and dated. A logo cut in the wrong colour is expensive and the argument always turns on what was agreed, so a recorded proof and a signature is the only defence a workshop has.
The workshop and the fitting team run on different clocks. Something produced on Tuesday still needs a slot with a van, a ladder and two people, and treating those as one schedule is how installations slip.
Sheet goods are bought whole. A job using two-thirds of a panel leaves an offcut that is either used within a month or thrown away, so tracking remnants turns waste back into margin.
Some jobs wait on somebody else. A consent application has its own timetable, and a workshop that starts the clock at approval rather than at the order keeps its promises intact.