Available appointments only showing on the hour

I have "Admin Side Time Base" set at 15 minutes. I have "Time Base" set at 15 minutes. But the only time available for a client to book is on the hour. The time allowed to book an appointment should be every 15 minutes.
There is NO "Additional time base" set, NO "Appointments lower limit" set.
Why are my available times only showing on the hour? There should be a lot of choices to book an appointment.
What is going on?