Doctari, I have hesitated answering this post since, IMO, it isn't very wise to give reloading info on bulletin boards. It's always best to go to the source, in manuals or on a powder mfg's web site. That said, it is perfectly ok to use the data you have for a 125 gr lead bullet with a 122 gr lead bullet. You're talking about only a 2% difference in weight. This is true if-and-only-if you got your data from a reputable source. As always, start at the min and work up whenever you change a component. But, do not use data for a 125 jacketed with a 122 gr lead or vice versa.
Power Pistol powder is a high energy powder with a fairly slow burn rate, slower than Unique. I see that Alliant doesn't give any data for it for 9mm lead on their web site, so maybe you should take that as a hint. But, again, if your data is to be trusted, you can use it for the 122 gr.