First of all, I'm sorry for starting a new thread about this, but judging by peppy's response to the thread, what I was saying was just misunderstood.
Currently, only the play that has the highest score rank is chosen for pp calculations. When choosing what play is considered for pp calculations, the best play (based on modified scores for pp calculation) isn't always chosen because of this.
Examples of when this can happen:
1) Player A gets rank 300 in a map with 95% accuracy, then the same player plays the map again and gets a rank 280 with only 90% accuracy (resulting in less pp because of less accuracy). So in the end, the second play results in a penalty in pp score. This goes against the statement included in the wiki that there is no penalty for bad scores. Another similar case is getting a high-score in a map with bad performance, that makes other better plays with less score don't count.
2) (This one I'm not sure because I don't have enough details about how the pp system works) Player B gets a rank 1 in a map with a 4-mod SSH, getting a good amount of pp. Then, let's say 2 years later, the pp gained in that map practically banishes. Now player B won't be able to get pp from that map again because he can't get a higher score in that map, even though he can achieve the same or slightly less score (that deserves pp based on the performance), another player then would get more (unweighted) pp than the best player with a worse performance even if they played the map the same day.
Maybe the easier way to solve this problem is storing the best performances separately from the best scores, but that would increase the server-load.
Edit: Since this could be considered more a design flaw in the current pp system than a bug, I will post in Feature Request for a possible solution to this.
Currently, only the play that has the highest score rank is chosen for pp calculations. When choosing what play is considered for pp calculations, the best play (based on modified scores for pp calculation) isn't always chosen because of this.
Examples of when this can happen:
1) Player A gets rank 300 in a map with 95% accuracy, then the same player plays the map again and gets a rank 280 with only 90% accuracy (resulting in less pp because of less accuracy). So in the end, the second play results in a penalty in pp score. This goes against the statement included in the wiki that there is no penalty for bad scores. Another similar case is getting a high-score in a map with bad performance, that makes other better plays with less score don't count.
2) (This one I'm not sure because I don't have enough details about how the pp system works) Player B gets a rank 1 in a map with a 4-mod SSH, getting a good amount of pp. Then, let's say 2 years later, the pp gained in that map practically banishes. Now player B won't be able to get pp from that map again because he can't get a higher score in that map, even though he can achieve the same or slightly less score (that deserves pp based on the performance), another player then would get more (unweighted) pp than the best player with a worse performance even if they played the map the same day.
Maybe the easier way to solve this problem is storing the best performances separately from the best scores, but that would increase the server-load.
Edit: Since this could be considered more a design flaw in the current pp system than a bug, I will post in Feature Request for a possible solution to this.