Appointments+ :: how do i make 60 minute service with 60 minute time base?

i have "employee A" who can only work from 8:30am to 9:30am on Monday - she provides a one hour service.

a) i set TIME BASE to 30 minutes.
b) i set DURATION to 60 minutes.
c) i set her WORKING HOURS to 8:30am to 9:30am on Monday

when i do this the reservations are shaded and not available

when i set DURATION to 30 minutes everything shows up fine and you can book the appointment at 8:30 BUT you can also book a session at 9:00 - i don't want this.

here's what i want:

when a user clicks on a date i would like the TIMES AVAILABLE table to show half-hour increments (since the time slot starts on the half hour) ... but when a user books the 8:30 slot they reserve the entire hour

and i need the confirmation to display 60 minutes and not 30.

is this possible?