Man, if you have 100 plays.
And you set a new play. All the plays under that one, worth less.
1° play worth 100%
2° play worth 95%
3° 90%
4° 86%
5° 81%
6° ...
... ...
Imagine you have 4plays, each one worth 200pp.
1° = Freedom Die 200pp
2° = Black Zenith 190pp
3° = The Small Blue 180pp
4° = Min Control 172pp
Doing four 200pp plays you will get a total amounth of 742pp.
Now you do a new Top play what worth 300pp.
But you don't get up to 1042PP (742pp+ new play 300pp) even being weithed 100%. Because all other plays you have under the new one are going down on the list, so they worth less now.
1° Heaven 300pp (New play)
2° Freedom Die 190pp (Before was 1° play so this was worth 200pp) now 10pp less
3° Black Zenith 180pp (10pp less than before)
4° The Small Blue 172pp (8pp less than before)
5° Min control 162pp (10pp less than before)
You lost 38pp from your other 4 plays)
Total PP = 1004pp
Non weighted PP 1042pp - 38pp lost = 1004pp after being weighted for the system.
Since all maps worth less due to down one possition from the new top play, after you set that 300pp play, you're actually getting +262pp on your profile. Not the 300pp, because all your other scores worth less.
This works this way, because other wise, someone could get rank #1 just setting 15.000 100pp plays. So the player who played more short maps would be the most high on the rankeds. Something what makes no sense if is a system what try to tell how good you're playing, and not how much did you play.
Years ago high ranked playeres where the ones what more score had. What leads into play longest easier ranked maps you can find to don't miss, wake up, play the map, pause, go sleep, wake up continue... No sense.