An empty home is the only time everything is reachable. No furniture to work around, no belongings to move twice. It is the easiest home to clean well and the worst one to clean badly, because there is nothing left to hide behind.
Move out cleaning is a deep clean done on empty rooms, which is why it is priced as one. If the rooms are not empty yet because the sorting has not happened, that part is organizing and packing, and it comes first. Landlords and agents usually want the appliances and the insides of cabinets done, so say if there is an inspection to pass and we will work to it.