Currently there is only 1 set of working hours.  However when you have staff based in multiple states and/or countries, you need to extend the working hours to cover the earliest time and the latest time  

 Eg: We have a Germany office, UK office, NJ office and an AZ office.  So my settings are set from 2am to 730pm. So because of this, our metrics are off. 

Suggestion:

Create Additional Regions or working hours based on UTC time / Local time

Add field for Technicians for location (or set their local time-zone)