Ok, heres an "Anarchists" view. Skeptic is a more polite term.
I talk to old timers, manufacturers, and look at really old threads and research and hers what Ive found.
The same coral will grow under a 6.5 kelvin metal halide, a 20k radium halide, a t12 fluoro actinic 55k combo, a t5 combo of any color, cheap chinese black boxes, expensive black boxes, stupid expensive leds that let the user guess completely wrong on color combos.
What this tells me is, if the light contains parts of the visible spectrum the coral can use, it will take it and use it. Intensity is the only question.
White. what color is white? technically is all colors evenly distributed across the spectrum, 6500k. Some whites we buy are 8000k some 12000k some 4000k. all are generally green limited .
Shadowing. An easy experiment. One flash light over an apple at 12 over the apple. make it one 48in tube over the apple. Its the size of the source. You can now take 3 flash lights over the apple. it fills in from the single source. the more small sources creates one larger source.
I dunno, but its possible the mix was more blue(blue has less par) but not necessarily less pur(what the croal uses).
I recommend to Par meter uses a Lux meter. You can measure overall intensity. You can get 500 par on just a blue channel, prob wont grow coral but its PAR....
I highly encourage this. I would add a lux meter to the mix, as it measures only intensity. And intensity is VERY important. More important IMO that the silly knobs the manufacturers give us to control color so we feel smart(or dumb).
Its a lot of these reasons that lead me to continually advise, set the color to YOUR eye, and make the tank look great. Then set the intensity. Minor chances in ratios are likely only aesthetic esp green red etc and even though it may read on the PAR meter the coral likely doesn't care at all. Esp when we keep in mind Par meters are used to grow green terrestrial crops.
Sound crazy yet? Look at DR Sanjay's tank. all levels at 100%. And some of the famous high end coral sellers have given us their secret color combos for radions recently. White channel only.