Yes Mayweather is on a heavier weight class. But when they rate "pound-for-pound", they rate all boxers not in accordance with weight. Mayweather used to be no.1 with Pacquiao as no.2, but now Pacman's no.1 since Mayweather's retired. But with Pacquiao's recent claiming of his 4th title in 4 weight classes (a rarity and a big accomplishment) , he probably could have gotten that rank away from Mayweather had he still been active also. Pacquiao is thinking of moving up to 140lbs to fight Hatton next year. I have a feeling the Pacman will be retiring by late 2009.
There's this rumor that came out in 2007 of him fighting Dela Hoya in the future. I think it's gibberish. LOL! But if it really does push thru, WOW!