Look, I'm not trying to argue with you, but you still don't seem to understand.
It
is as much the increased area per light as the increased intensity that gives a 1000 watt light value. 1000 watt lights are very efficient in terms of converting electricity into lumens, which is the lumen rating of the bulb. On paper, they are very intense in lumens.
However, a 1000 watt fixture cannot be placed as close to the plants as, say, a 400W or 600W--although these may not be as efficient, both absolutely, and because you'd have to run two to cover the same area at an equal or greater intensity. Thus, if you're producing more from a 1000W grow it may be simply because you have more plants--they lumens they are being delivered may be less than that of a couple plants close under a 400W. Plain and simple.
Don't believe me? According to J. Cervantes in
Marijuana Horticulture: The Indoor/Outdoor Medical Growers Bible (2006), 1000W HPS is 140 Lumens per Watt, and at one foot away is 140K lumens but at 3 feet away is 15.5K lumens. Meanwhile a 600W HPS is 150 LPW, at one foot away it delivers 90K lumens and at 2 feet away 22,500 lumens.
Even though 400W lamps produce fewer lumens per watt than a 1000 watt bulb, when properly set up they actually deliver more usable light toplants. The 600W bulb has the highest LPW and can be placed closer to the canopy of the garden than 1000W or 1100W bulbs. When the 600W bulb is closer to plants, they receive more light.
A 1000W HID emits a lot of light. It also radiates a lot of heat. The bulb must be further from the plants to avoid burning them. In many cases it is more effective to use smaller wattage bulbs. For example, two 400W bulbs emit light from two points. The disadvantage is that two 400W systems cost more than one 1000W system.
So unless you're going to tell me that Cervantes is wrong and is misleading the noobs too, I'm going to keep saying what I'm saying and will keep insisting that the distinction is significant even if you don't quite get it (which I can't quite tell if you do or don't.)
Seriously, I'm done with this now. This kind of squabbling doesn't belong in a thread this awesome.