Good Morning Shed.I'm 100% sure that depends on how the lights are configured and their spread patterns. For example, Thirvnrob had his lights end to end and didn't think his plant in the middle was getting enough light. Rotating them each 90º filled in the middle space.
Or Skunksta who had his lights side by side and it was creating a hot spot in the middle, which was eliminated by rotating them 90º.
I see your sig has changed.
What is with the little symbols?
Hope you have a great weekend.
Take care.
#VIVOSUN #Love What You Grow
Bill284