On several occasions in the past, the punch mitts on Roach hands came out flying when PAC started to explode in their numerous punch mitts sessions... If Hoya was not able to do that during the time Roach trained him then Freddie Roach can say with authority that "PAC hits much harder than Hoya"...
Have you heard of acting? If Roach wanted, he could scream "Ooooooooooouch!" everytime Pac hit his mitts or pretend he just can't take it anymore and then look at the cameras and go "See? He hits harder than Oscar!".