Why does MS rename postfix queue IDs?

[Mike Jakubik]

So, as the topic says, why does MS rename postfix queue IDs? Whats is 
the reason for this?

--
Apr  2 15:34:01 fbsd postfix/smtpd[18878]: 1EE3E2B2036: 
client=localhost[127.0.0.1]
Apr  2 15:34:01 fbsd postfix/cleanup[18879]: 1EE3E2B2036: hold: header 
Received:
...
Apr  2 15:34:04 fbsd MailScanner[17694]: Requeue: 1EE3E2B2036.F1395 to 
F39462B2043
--

Why add the .##### to the ID? Also, is it really necessary to change the 
ID when re queuing the message?