In fairness there's too many unknown variables (traffic, delivery waiting, weather etc etc) to know when they will be delivering something as the schedule is non linear. The sequence can also change throughout the day due to traffic conditions. I would be surprised if the algorithm is set at 5am and does not change as the day progresses
For example, you have to deliver 300 items in and around the city you live in. Can you tell when the 178th item would be delivered?
The best they could realistically do is tell you when they are, say, 10 away from you and that would be in around an hour. Some couriers do this.
Most companies give you a time slot of a few hours.
You can follow the progress of your delivery on their app.
But why even bother to claim that it's possible to track your parcel, when that is clearly not the case.
Royal Mail's site is a bit pants.
The best way to catch your RM parcel is to be at home when the postie comes.
Ours comes only once a day, between 11.30 and 12.
In December, they also do weekend deliveries.
Make friends with the post person and show them a safe place to leave your parcels.
You can pick a safe place on the site too, but they won't check.
Or get it delivered to your work or to a post office.
Living close to the metropolis of Leeds means there are several Amazon warehouses within spitting distance and I'm about to order some stuff for delivery today with no extra charge. All tracked and can't fault 'em.
In my area Amazon is excellent.
Trouble is they have an agreement with Royal Mail too, so sometimes my Amazon comes with the postie, who might take it back if I'm not in - well, they don't do that anymore after I pulled them for it
I do however give my post people a Christmas gift!