The Turnaround hours check has been updated to allow you to either include or exclude office hours. There is a new flag in the System Parameter that can be seen below.
For example, let the Turnaround Hours for a car be three hours, which is less than the set 10. So, if a car is dropped off at 3:00AM and the office hours open at 7:00AM, the car won't be ready three hours after it is dropped off. It will be ready at 10:00AM, three hours after the office hours open.