I got a candy a while back, what I found is that if the light is too strong it will not expand very well, may even re-gress.
I moved it to a location hanging off a "rock wall" where it only gets indirect light and during the day it now has much larger expansion, seems much happier.
the more I work with corals the more I look at what they do.
if they open and have good color then they are probably ok.
in a day you can see them react to a new location and then decide to leave them or move them.
that is -- a day *when they are not stressed* from shipping etc...
so if the coral was shipped then you need time to get it acclimated.
start with low light and move up over several days.