What does "overnight counting" mean?

"Overnight" is referred to as "Overnight" for short, that is, "Overnight" and "Overnight", which is the calculation unit of hotel room occupancy rate in a certain period of time. Because there are late check-in, early check-out, hourly rooms and so on. In short, it is the number of rooms rented per night (including "actual occupancy" and "paid reservation vacant").