OP: I added my wife as AU on Discover More 2 months ago. She got reported a week or two after that. I then called CSR to ask to convert wife to "Joint". CSR said I would have to fill out a form. They mailed me a form. Filled out with signatures of both. About a week later both of us got reported to 3 bureaus as "Joint Account".
Thank you for the answer, one card is about to report on the 19th fingers are crossed.
AUs do report. I added my mom as an AU to my Discover card and it reported almost immediately. She is also an AU on my CAP1 card and Chase Freedom to help her credit. They all report.
Just my 2cents - I have added my wife as an AU to ALL my cards (listed in my signature). They are ALL listed in her report regardless of lenders asking for all the info (like Amex - my wife's SSN etc) or just her name (like GECRB)...