2 step is a tighter colour bin, meaning its deviation from 3500k is slightly less than 3 step bin, or put another way the colour bin area is smaller, more useful for Architectural lighting than grow, tighter bins typically more expensive
Cheers
Mark
to put that in laymans terms its like youre at the mall and look up and see all the lights - its about the look of the lights matching exactly in hue/spectrum which is not relevant for our application