Where did pac's "power" go?

[Just looking]

He went up in weight and his power didn't carry on to the 7th one. Plus, he was fighting guys with a big reach advantage on him so it became harder to land that one punch. But he still was knocking guys down, so his power kept with him, just wasn't as effective in that weight.
Ah, if you bring up Cotto, it's very easy to explain. Cotto was one of the smallest WW and was a perfect match up for Pacquiao. And it still took him 12 rounds of a beatdown to get the stoppage