Could be, seems to me both numbers have been used.
Even still, 10k hours, just getting warmed up.
I know these are plasmas and not cars, but what is 10-20k on a plasma that will (hopefully) last 100k?
I suppose decreased brightness is the big factor, but I do not see that as a negative; I am one of the few (oddballs) that think the 500m is pretty dern bright! Compared to a Panny X1 I have, I would guesstimate the Pioneer to be capable of 2-3 times brighter.