The same "pod" of agents that handle regular services is cross-trained to handle travel. If you book through a human being on that pod, it will not be an Expedia booking. You do not want an Expedia booking if you ever have to change your ticket. Trust me on that. You will spend hours of your life on hold. If you book through amextravel.com, even when logged in as a Centurion member, it will be an Expedia booking.

The "pod" system has been a disaster. I believe AMEX knows this, and has (allegedly) stopped taking new Centurion members because they don't have enough resources to deal with the existing customers. My guess is it became easier for AMEX to overload a "pod" as opposed to an assigned person, and that's what happened.