I am not sure why you would dial down your lighitng, especially LED. I have found that SPS coloration improves with specifically more UV light, I doubled the UV LED's in my tank, and color improvment is significant.
If they came from a tank with dual T5 and went under a LED at 90%, they'd bake in about 3 days Dialing down to match the source lighting is a good idea. Then slowly ramp up