OK, that all makes sense. I suspect perception plays more of a role than actual emitter variations because surely to actually *see* a difference in output from two emitters the actual lumens readings would have to be significantly different, more so than the cree lottery would suggest.
For example, can someone really see a 10 lumen difference in output between two lights or is it gonna be more a matter of perception based on a variety of other factors such as beam pattern? I find it hard to see a 50 lumen difference in some cases.