1. Glare is wasted photons. If you need to cover your light with a thing to reduce glare, or mount your lights above the silly low recommended 7", you have a light that isn't sending the light where the light is needed. 2. Has everyone forgotten the awesomeness that was the G4? Both spectrum and PAR
in the tank. 3. Given the forgotten G4, we've also forgotten that the 120° wide angle kit was intended for shallow tanks and "spread [will be] achieved by dimishing the peak PAR at the center of the fixture." Maybe BRS meant "diminishing." 4. Now the G6 is at 126.3°. Or, wait for it...back to 77° with the comically named "High Intensity Lens Kit." The G5/G6 spread greatly reduces photons being sent into the tank. Your PAR readings are accurate. 5. That G5/6 spread performed VERY well during BRS testing. Not a surprise. Also not a surprise that performance at home is other than what BRS has shared. We generally don't reef with an empty glass box full of freshwater sans rocks, maybe sand, frag racks, stuff growing on the glass, corals, and fish.
If you move from G5 to G6, you will most likely see a drop in PAR. If the spread increases, PAR will generally decrease. The easiest way to see that is to test open-air. That's one of the reasons why I test open-air.