mitsubishi hc3800 lamp life and brightness

i got to about 400h mark and it seems as though the lamp is dimmering, i now have to use BSPLAYER because it has higher brightness compared to other softwares could it be that at the 400h mark the projector dimmers so much?, i would say i'd lost around 30% of brightness, i cant see hair in the dark anymore if use VLC player or total media theater.
i tried different settings but it seems like it has to do with the hardware itself.
any thoughts? did this happen to any of you?

ah i didnt know that, good to know. ill try and recalibrate then.