Calendar time vs Buffer time

I like the idea of "Buffer time your customers can't book". I like to give myself 15 minutes between appointments to go to the bathroom, check email, jot down notes from the previous meeting, drive to the next appointment, etc. However, when this option is turned on, the calendar entry shows the booked start time 15 minutes before when the customer actually booked. I either show up or call the customer 15 minutes before they are expecting me - bad form! My calendar should show the exact time the customer booked the appointment, not the time minus the buffered time.