Oh, I'm sure there's a few that have. But they are far outnumbered by the majority.
Millsap was more efficient offensively backing up Boozer in his final year, then when he took the starting reigns from Booz. Not to mention Millsap's defense was 10x better as he could play his heart out, and not have to worry about picking up too many fouls or carrying the offensive load.
Monta Ellis was far more efficient playing limited minutes. Once he got big minutes from GSW, he started taking more and more shots and his efficiency took a nose dive.
More minutes means more shots means lower FG% means less efficiency. This is why per36 doesn't scale, at all. The only thing it is useful for is comparing players who are playing similar minutes.