It keeps the light more balanced across the canopy. Light projects out from a single bulb in a conical shape, like water from a shower head,  so where to 2 conics cross the light is more intense so the outer conics with no bulb next to them are the weakest light intensity, so it makes sense to spread them out and that big air gap has to help cool them.  I have never understood why they put the LED's on one cluster, but there is a lot about light I dont understand.

Thanks again for the tip on the Growcraft lights.