What I like is that an approximate time is given, ...

What I like is that an approximate time is given, which is even refined during the current day.

Unfortunately, the appointment change did not work.
Originally my shipment was supposed to be delivered on a Thursday.
Since I was not at home that day, I rescheduled the appointment to the following Saturday. Appointment would be confirmed so I waited all Saturday in vain.
Monday was then delivered.