well the bike will compensate for some, I havent seen anyone post dyno charts about it really though on here, and horsepower will obviously be affected but how much I dont know, but the air fuel ratio is whats important. having a pc3 your just adding or taking away fuel in certain rpm's and tp's.... but the ECU will compansate for barometric pressure.
My thoughts on this is the tune that you have on your bike will most likely be ok to run at all elevations but the bike will yield more or less horsepower where you are... higher the altitude the less the horse power since less air density.
I think the only thing you could do to make sure your on the safe side is dyno tune it where you ride the most, and then have it checked out on another dyno, as long as the air fuel is near spot on you would be ok... dont worry about hp numbers as they will vary anyways.
just my $.02