600w hps lumen output

Hello,

I just got this bulb:



It says 85k initial lumens. I've heard 600w hps usually outputs 90-95k lumen, does this mean this bulb is low quality?

Also, im coming from a 400w hps and I was wondering if someone here did the same. Is it really worth the upgrade from a 400 to a 600 (yield/quality wise)?

Thanks