Yeah, everything I've read says (for LED) 65cm / 24" once they pop, for at least the first week and change - I'm personally of the mind that since I have a relatively weak UFO (135W-90W actual) that I can cheat that in a bit but I'm at 20". I'm going 24/0 to maximize veg/stretch so I can get the outer bud sites some better light away from the main cola down the road...once I start introducing nutes, i'll start giving them a breather at 20/4.
Just my theory and reading. I think it was Tang's post that said 65cm for seedlings.