http://jumba.com.au does this as well; when on the phone to you, they ask you for your password, and the customer support person checks it on their screen.
Are you sure of this? The CSR could also be comparing the hashed/bcrypted/whatever version of the password you give them over the phone to the hashed/bcrypted/whatever version stored in the database.
Given they do this sort of thing, even if they did do fancy hash comparisons when I called them, they still have people's passwords hanging around in plain text elsewhere on the system.
(What could possibly go wrong?)