Workflow to trigger if work done outside of normal business hours

I went to create a WF to trigger if a Service Activity contained work done outside of normal business hours today, but when i went to create it, I realized there is no (OOB) functionality to test for the Start Time of a Service Activity against a time of day.  It can only test against specific date/times.

Has anyone else run into this and have you found a solution?

Thank you.