Originally Posted by
IMOA
This may be a bit redundant for the conversation but the 16 segment limit applies only to future segments on the ticket. I just completed an e-ticketed AA 19 segment DONE4 by adding the flights in half way through, this was something I was going to do anyway but it does mean that you can do a 20 segment e-ticketed AA *ONE, you just need to pay a $120 fee for the extra 4 segments. Yes, sucky and not fair but better than not being able to do them.
I hope the agent knew what s/he was doing. On one occasion AA handed me reissued xONEx tickets that worked fine on AA segments, but when I tried to check in for a flight JFK-HKG, Cathay's computer decreed my ticket to be worthless. Fortunately I had time, and the Cathay agent went off and reissued the ticket (gratis) properly.