Please see thread: https://premium.wpmudev.org/forums/topic/free-time-is-not-showing-on-my-page. Note that I didn't see a way to respond to the postings.
This is what I have on the page now:
[app_schedule service="1" worker="23"]
I have service set to ID 1 and a worker set to ID 23.
The "Working Hours" are set to be FREE for worker 23 until 7pm tonight.