wilderness - 1:32 am on Oct 3, 2011 (gmt 0)
I've had ATT/SBC for nearly ten years and have NEVER been assigned a PPPoX Pool - Rback range.
Perhaps your variation in dynamic assignments is related to LSA.
I monitored my websites visitors for more than ten years and then compared those IP's to email communications in order to confirm identities, making adjustments in the process. Also supported the efforts with tracerts.
Thus, Ive sympathy for your indifference, however what I previously provided are accurate statements.