It comes down to the same problem that I discussed earlier and that is the practics of getting 1 x 0.5 watt LED to fit into the same space as 1 x 0.06 watt LED, or comparing a 5mm LED to a 10mm LED. They are not the same physical size.
So in the same space you would have either something like 140 x 10mm LEDs or 280 x 5mm LEDs...
On a macro scale its no different.
Take the UFO for example, lets say its outputting 2000 lumens per square foot at 1" above the plant canopy, if you had 2 x 90watt UFOs you either have them both light the one 2' x 2' space and double the lumens per square foot of light on that space, or, you have them light their own respective areas 2' x 2' of plant canopy and the lumens per square foot remains the same except you are lighting a wider area.
Focussed at a 2' x 2' space, the UFO would give you 500 lumens per square foot (2000 divided by (2 x 2)). Two of them pointed at the same grow area would give you 1000 lumens per square foot and so on, 4 would give you 2000 lumens per square foot, if all 4 were angled down into the same grow area...without having to physically raise them high enough that you may lose lumens.....
That is the nature of LED light because of how directional it is and that is when it starts to get inefficient, because although these are rough numbers and it may well work out that 4 x 90 watt UFOs mounted at 6 inches above the canopy and focussed onto the same 2 foot x 2 foot plant canopy area, may work out to outputting a higher amount of lumens per square foot than Ive listed, the fact of the matter is you are now at 360 watts of LEDs ( 4 UFOs) and getting 3000 to 4000 lumens per square foot of LED light (generously speaking) where if you used a 400 HPS HID with reflector you would be getting 13,250 lumens per square foot in the same grow area of 2' x 2'.
So this is where the CREE/Luxeon type LEDs are doing a better job because they are giving more lumens per square foot, and per LED. What we need is for someone that owns the latest Procyon 100 to test its lumens output for us so that we can get an idea of what lumens per square foot they are getting from their lamp which has 56 Cree LEDs mounted in it.