Sending a projector to someone to calibrate it will not take into account your screen, room and ancillary equipment. So seems a shame to do half a job on such a decent projector. I don't know if they still do it but some projectors were 'calibrated' from new before shipping, which is even worse in my book since the lamp changes so much in the first 100 hours that even if it was done in your room the drift would make the calibration next to useless. If this RS35 was calibrated when new in such a way, then for all intents and purposes treat it as if it isn't calibrated at all now at 500 hours.
"Don't believe everything you read on the internet". William Shakespeare 1615