I'm not even sure. My 0 Corruption playthrough has 337 PP and 34 Skills. I could obviously get it higher if I chose money from Tiffany or power from the Shopkeep but it's unlikely that a 0 Corruption run can get to the max amount of power. That being 363 PP. I'm only guessing but if you did a perfect 0 Corruption run, I think you could end up around the 350 PP ballpark. If you let Laurie die then it should be easier to cross but I feel like that goes against a 0 Corruption playstyle, personally.
For my max corruption dude, he has the max PP allowed, 363. His corruption is 49. It's impossible to reach 363 PP without letting Laurie die. At least, in the current update. You would be missing out on the power that Aglaecwif gives you. This is all from a legit playthrough. You could obviously edit your stats higher if that's your thing.
So I believe there's around a 10 PP gap between a 0 Corruption playthrough and a Max Corruption one.