If a slot is booked by someone and then cancelled, it still counts as a normal booking if the same slot is rebooked by the same person even if it is within the 24 hour exemption period.
The idea here is to prevent people from gaming the system by cancelling a booked slot just before they go out and than rebooking it within the 24 free booking period.
Looking at the history, it appears that is what happened in your case - your reservation for 8/3/13 at 9am was cancelled and rebooked - so even though you were in the 24 hour period, it still counted against your time.