Appointments+ timebase and starting times

I've set the timebase to 45mins and set the first appointment to 8:15am. However when I look at the appointments on the frontend the first appointment says 8:00am which I can't select, the second is 8:45am, and the 3rd 9:15am. It should be 8:15am as the first appointment based on the schedule I set. Why is this?

You can see the schedule here: