There's a huge number of lunar's out there, so not surprising to have a morph, very cool looking.
And yea, you'll get huge variety of sizes just depending on situations. Most people keep their paly's somewhere where they "puff" up a bit more, but under higher light they'll shrink down to a smaller disk. I have a colony of lunar's that's about the size of a dime or larger in my display, when I put a frag of it in my frag tank where it's much higher lighting it shrinks down to about an eagle eye or radioactive dragon eye sized polyp.
HTH!