Why does freddie Mercury sing Bohemian Rhapsody different throughout his career?

One thing you might notice is during live performances Freddie often sang some of the notes an octave lower than originally recorded. When Freddie was in the controlled environment of the studio and not running around on stage he could push his voice to do amazing things. Live, he was more interested in entertaining than reproducing what had been done in the studio. Freddie also had nodules on his vocal chords which caused him some problems especially singing high notes. Once again, in a controlled environment these weren't a problem. Live, however, he chose to sing some notes an octave lower to gain better control of the note. He did this with most of his songs. He also hated to be bored and I'm sure singing the same songs night after night forced him to be creative at times.