It's cool to see how Amazon sorts the tracking entries descending by date, while UPS does it excluding the shipping entry (probably stored in another table), sorts the rest of the entries and -then- appends the shipping entry. Most likely, the guys at Amazon don't trust in the API UPS might have provided them, and end up sorting what they get, just for the "what-if"...
I don't think there's (a huge) WTF in reusing tracking numbers, as they simply may run out of them. But if I had written the software, I'd wipe all the history of a tracking number before starting to use it, as it might have been previously used.
It does seem that they don't have a tracking of their own tracking numbers, and -that- is TRWTF.
By the way, the books haven't arrived yet...
Mahoro