One observation I noticed about the growth of my Elegance, Golden Leather, and Kenya Tree is that the dirtier the water was, the larger they grew. Same thing happened with a dark orange or brown Zoa colony I had. One day when I had my 100 gallon up and running my skimmer pump died. I put off buying another one and over the course of a month or two I noticed a rather large increase on those corals in growth. In fact, I thought I was losing my Elegance (started with 4 cups/mouths, slowly shrank down to 2), but then after that it grew back to about 6 overall disks/mouths.
Sometimes I feel these corals types are better suited for people, like me, who are a bit more lazy in tanking care of their tanks. I'm pretty bad.