Well, sure, the 400W and 1000W are cetainly brighter ... no arguing that ... I was just pointing out that a 400W isn't 1.6x brighter than a 250W, even though that's what the math works out to. (And a 1000W is definitly not 4x brighter than a 250W!) So, the 400W you tested was a 20K, then? That certainly makes sense. Because you didn't specify, I assumed the bulbs were similar. If that were the case, reflectors would have been the likely suspect, right? It's not fair to compare a 6.5K to 20K in terms of PAR ... heck, it's not even close to fair!