This feature is available for SMB machines. Refresh the browser page and check if you have a notification asking you to refresh the page one more time. Click Yes on the notification and then the SMB admin page should change, and then you will be able to add specific hours to exceptions.
Thank you. I was asking because my client updated to V20 and the option was'nt showing.
I got an answer from an another thread where it specifies it need to be on V20 update 1.