But my bigger suspection is still on coverage side, more specifically for those offcenter areas on Y dimension (from front to back) Gasman's system have Acropora everywhere in around 48"X24" area, we know that one need at least 200 PAR for decent color and growth for Acro, many Acro demend more. If you look at
Sanjay's par testing for below plot chart from single AI unit at 24" distance (From picture I guestimate Gasman units locate at around 12" above water, so below is corresponding to middle level in the tank) there is around 12" X 12" area with 200+ par, on X dimension (from left to right) there is help from overlap of nearby unit, but since Gasman only have 1 row of AI units, on Y dimension each unit is pretty much on it own. I suspect Acros in offcenter areas on Y dimention are not receiving enough light, I am wondering if Gasman you have a PAR meter that is best way to know.
For reference below is Sanjay's chart from a 400W MH on good reflector, at same 24" distance you are looking at about 24" X 24" area with 200+ par, certainly there is no meaning for 1 to 1 comparion but what I mean is that if you want to replicate lighting from single 400W MH (which is currently running on many SPS dominant tank) by AI units, you probably need more than 2 units, or 2 units with some supplemental, that is awefull expensive given by current price, not sure if it can reach breakeven point before replacing LEDs.
Maybe the solution is system like Lucas, which combine 40 and 90 degree optics , but there is no such product available in states. Even there is, it will most likely be very costly.
Myself is researching for lighting of my future upgrade, for now I will prob. stick to original plan which is 10 bulb ATI PM and see if it is possible replace few T5 slots with some sort of LED tube to add some spectrum and dynamic looking.