How will the mass be different? Oscar is coming down to 147 so he likely won't weigh in as high as he does at 154, and Mayweather was 149-150 coming into the ring against Oscar because he doesn't really put weight on from weigh-in to the fight. Pacquaio weighed 147 for a lightweight fight. Thats more then Mayweather weighed against Judah, Sharmba, and within 3 pounds of what Mayweather weighed in at against Oscar, Carlos, and Ricky. I don't get how you conclude that Pacquaio will weigh less than Mayweather did?