Why did I only gain 30pp when the map I played gives 100pp?
PP is a weighted system. This means that your highest pp score gives 100% of its pp, the next one 95% and so on. Therefore, a 100pp score that you just obtained may only be weighted around 30%; however, this doesn't mean you actually got a 100% pp gain. Even if you set a new personal top pp score, every other score you have will be weighted less than they did before. It's quite easy if you think about it for a little bit:
Let's imagine that your top rank only has 2 maps and looks like this:
- 100pp (weighted 100%)
- 100pp (weighted 95%)
Your total pp will then be 100 + 95 = 195pp. If you now set a 110pp score, your top rank will look like this:
- 110pp (weighted 100%)
- 100pp (weighted 95%)
- 100pp (weighted 90%)
I used to get some pp from playing 100pp maps, but now I get nothing?
This happens for the same reason as above. At some point, the score will be weighted for 1% or less, and your overall net gain of pp will be so small that it's negligible. Set some scores worth more pp to gain more!