Um, yeah, leaner, richer, in, out, less dense, more dense, ipso facto, QED.
Except the last time I did this, I could swear I had to back them out to get more idle revs at altitude. Maybe that's only in 'R' months?
I do know that someone comes on here alla time lecturing us about how the idle 'mixture' screws don't affect idle mixture at all, but rather the volume of stuff that gets spritzed down the hole when the butterflies are shut, or nearly shut.
Don't know much stoichiometry.