FaceTime over mobile data question

Hey guys, I wonder, can someone clarify something for me? I understood that AT&T was now allowing Unlimited users access to FaceTime over mobile data as well, a shift in the original policy of insisting that you have to switch over to a "Share Plan" or whatever it was called. Am I imagining this? I just tried to get it enabled, to be told that it isn't supported on Unlimited plans. Cheers.