well its a fact that pac had a hard time losing weight and was weight drained in several fights. he lost a belt outside of the ring cause he wasnt able to make weight. he also suffered a KO loss for the same reason.

the old pac just punches in bunches, he still does but at a pace. boxers who fight like pac doesnt have a long shelf life in boxing simply cause he needs a ton of energy and stamina to be effective. age plays a big factor and now that he is getting old roach thought him how to pace himself. to rest in between punches in bunches.

the pacing plus not losing weight at all before the fight is the reason for the higher punch stats compared to lower weights.

he also gained more mass simply cause every person in this planet does when they become older. plus he is now fighting in higher weights and for his small frame he can bulk up with good muscles.