I don't have any way of measuring lumins,PAR,or anything, BUT...
I HAVE been 'getting away' with being 'under-powered' , running 480 watts worth of QB 120s in a 3 x 5 area , and having to turn them DOWN sometimes...
I 'm currently 'getting away with' 600 watts worth of QB 132s in a 3 1/2 x 5...