В Справке (Help) по программе Microsoft CRM встретилось выражение billing hours. Подскажите, пожалуйста, как его корректно перевести ?
Вот контекст:

In , a billing day is based on the working hours set in your personal options. For example, if your start time is 8:00 AM and your end time is 5:00 PM, your work day has 9 billing hours. By default, an appointment scheduled as an all-day event is also 9 hours long, but you can change this if you want.

The box displays the actual number of billing hours you work. This means that if you set up a closure from 8:00 AM to 12:00 noon, you're closed for 4 billing hours and open for 5 billing hours. An all-day event is 9 billing hours (or whatever your default is set to); two all-day events are 18 hours, and so on.

Это часы работы или что-то иное?

Заранее спасибо всем, кто откликнется.