I just ask a rep online about FX being in AT120 when I was switching over to it a few minutes ago. He said it wasn't included. Probably another ploy to trick people into staying. I didn't get the Starz deal either.
I also chatted online with them, and they didn't know anything about it, but I agree, it's most likely a way to get you to stay, but I'm perfectly happy with AT120. Don't need anything more...