I had to dig a bit but this is why I always figured they are palys…The corals in your photo are Zoanthus vietnamensis.
When I got them they were misidentified/ mislabeled. I guess the old method, small is Zoa, large is Paly…
Learn something new all the time.
I am eyeing the book you mentioned “Indo pacific corals”… but the $$$ is steep….
Regardless very educational discussion on zoa vs paly…