I'm not a fan of the lower light = better color for light loving sps. I think the popularity of this idea is driven by lower utilty bills. I run MHs for 8.5 and actinics for 9.5.
Keep in mind corals originate from an equatorial environment with almost equal day and night. Then shave an hour or two off each end for dusk and dawn and they evolved expecting 9-10 hours of full sun, not just wee lighting fixture output.
There are theories that the bright pigments on the axial coralites (those at the top of the coral, closest to the light source) are performing a sunscreen function, preventing scorching of the tender growing areas. This suggests more light results in more and more intense color.
And in my personal experience, my sps had the brightest and most color when I was running my halides 9-10 hours a day.