He's always walked around within range of light heavyweight but he was dominant at heavyweight he saw no reason to cut weight. However, towards the end of his career, when he was being out fought by bigger fighters who were changing with the game, rather then actually cut down to light heavyweight he chose to call it a career and retired.
I do agree with this.
I always wanted to see Fedor get himself more "ripped" and fight at LHW, which seemed to be his more "natural" weight class. IMO. He'd have been a beast there. Probably still would be.