Seems like you don't know how pp system works, you won't obtain pp just by getting an S, it needs to be a full combo at least with a nice accuracy, and also you have to make sure it will worth some pp for you, you can get SS on easy maps and they won't give you any pp since probably they are not close to your playing skills. As long as you get better scores and reach a higher rank, then it will be harder to get pp since you will be required to get even better and better scores and play harder maps to get some.
If any map you play would give pp then it would be so easy to farm, it doesn't work like that, if you want more pp you have to earn them, they won't magically appear by playing any map and getting an S rank.
Anyone knows whats happening?