well..i am no expert but from what i was told, sudden high out put of lights from total darkness can really stress the fishes and corals. corals tend to stay shrivel up and produce mucus which really cause some problems when in contact with other corals. i know with my 144 watts of light all turn on at once, my corals seem to stay shriveral for a few hours. i dont know if that is in direct connection with the out put of lights but after i put speerated switchds on all 4 of my light bubls, the corals and fishes seems happier and dont seem as stressed.
my experience, my corals open completely when i turn on each light bulb one at a time. but when i do turn all on at once, basically most of my corals stay closed for a long time and when open, it dont seem to be open completely. i dont know if this helps but i hope it does =).