Thank you. Here's why I continue to be confused (there are many reasons, but here's the main one): I just spoke with the RTW desk, and this is how they described the process for e-tickets vs. paper tickets.

E-tickets: Each and every routing change results in a $125 fee and is effective instantly. That is, the ticket for the new segment "reissues" with each change, and I would receive a new ticket number for that segment on the spot.

Paper tickets: I receive a new ticket number for a new segment following a re-routing only when I physically turn in the paper ticket. Therefore, I can make multiple routing changes to a paper ticket and pay only a SINGLE $125 fee if I wait until all my routing changes are complete before I physically turn in my paper tickets and get new ones. But, the catch is that any seat I am holding on a "new" segment is really only held temporarily, because I don't have an actual ticket number associated with that new segment (which doesn't happen until I get the new paper ticket). Accordingly, a foreign carrier (say, CX) could cancel my seat on their carrier if I wait too long to reissue my ticket. Accordingly, while I can book a new paper ticket routing over the phone, if I want to be sure I'm holding that seat, I need to go in to an AA office and physically turn in the ticket (or mail it in), pay the $125 fee, and potentially pay a $125 fee again if I later make another routing change.

To be clear, none of this is based on personal experience, just what I've been told be the AA RTW desk. I also think this is consistent with what DownUnderFlyer wrote above, although it's a bit of an elaboration on it. Does my description sound correct?

Thanks.