Punchstat numbers are BS at times. They don't count punches on arms and against the body. Pressure fighters have always used the ability to beat an opponent anywhere on his body to slowly break him down. Marciano would hit fighters in their arms until they couldn't lift their hands any more. Of course Mayweather made all of this moot by knocking out Hatton - which is exactly what you're supposed to do - but these punchstats do not accurately reflect Hatton's efforts.
I wasn't exactly counting but Mayweather did throw in a lot of body shots. I doubt Hatton would come out with better statistics, even on body shots alone.