I see what you're getting at. Maintaining the pentecostal vs. charismatic distinction. Historic pentecostals still held to some [inconsistent] form of sola scriptura (adding tongues and prophecies). The pentecostals of old at least wanted to back up their miraculous gifts from scripture. Later charismatics, however, have moved away from this and many have almost no biblical underpinnings. And they don't even care. Many modern charismatics I've come across conduct themselves as if we're in the days of Noah with no scripture and just receiving words from God directly. No bible needed.
This latter development may have a tenuous connection with postmodernism (as I wrote above). However, this connection would not be an embracing of postmodernism. I think the connection would more like this. Postmodernism has affected our culture and, therefore, thinking. Many, if not most, charismatics have let their thinking be shaped by the culture, and not scripture. But I don't think charismatics embrace charismania with some philosophical understanding of postmodernism. Rather, I think the postmodern cultural context that has shaped them has instead provided them with the impulse to jump to charismania.