Doing this on a Roland is a snap. No need to use the Style Creator. Makeup Tools puts all the commonest style editing needs in one simple place.

Adjust Tone, effects, octave, dynamics (both Volume AND Velocity) for every Style Tone (not just the Style Part, for styles with different sounds on the same Part), and then store them as either offsets (so the original data remains intact, or 'freeze' them to those values... And you can do the same editing to every single sound in a drum Part, too!

TBH, the Makeup Tools are still one of the primary reasons I choose Roland's over others. They make tweaking styles and SMF's easier and more comprehensive than any other make.