The pseudotenacles just look too elongated for a hairy/frilly mushroom. At first I thought it was an anemone until I saw the rim around it laying flat. Maybe someone else can chime in that has the same thing.
I have not been able to find many good pictures of Amplexidiscus species except for A. fenestrafer, and it does not seem to be that but does look similar in many ways. In looking for Amplexidiscus pics I found a few Rodactis pics that looked distantly similar, but the description does not seem to match.
The LFS wanted $30 for them, I didn't think that it was a Ric when we purchased it, but the store insisted that it was, so wanted more for it. I felt it was worth it because it was so different than anything that I have seen. I have already been asked to go and get the other one, it has been a week so we will see. Hopefully it will multiply like a mushroom, not a Ricordea, then more people can get it. The one I have is about 1.5" the one left behind was about an inch.
Well if it does inflate more, I haven't seen it. It does look a little beat up, it fluoresces more under moonlights now than when I first got it, but the only change I have seen is a little more blue in the mantle. It is eating, excreated waste twice. Maybe it will change some more.