Currently we have the following setting:
“Use service duration as booking time slot
If enabled, the time slot step will be the same as the duration of the service on the booking calendar.”
When checked, this is applied to both the front end (booking form) and the admin panel.
I think there should be an option to not apply this setting in the back end so the admin has more control. Especially if they are creating bookings outside of hours or at intervals timings unavailable in the front end.