This is pure speculation, but it is possible that Ticketmania can no longer sell the FITS tickets at this time, since FITS cannot be advertised on a broker's web site.
The only difference I noticed between Ticketmania and Paramount is that Ticketmania had a special URL that you could type in to order them on-line, and Paramount did not. The URL did not appear to be directly linked from their normal ticket sales pages, but there was a page present and perhaps this was too much for Disney. I also believe that Paramount has always sold them by phone call alone and that is why they were allowed to continue selling.
This is of course all speculation, but it does seem to fit the puzzle so to speak.