Setting Work Schedule with Outlook an half hour boundaries

We use Outlook at work for scheduling. By default, the work schedule is 9AM to 5PM. You can easily change this to other hours under Preferences, but you are limited to full hour boundaries. I can't, for example, change my start time to 8:30AM, I can only choose 8AM or 9AM.

Is there is away to set a start time and end time on half hour boundaries?