The rank system is working as expected. Your rank naturally falls from other people beating your scores, and the change is only reflected when your score recalculates (this can occur daily and usually only shows after achieving a new score).
What NixXSkate said is right. You never lose PPs for a new play, be it good or bad.http://prntscr.com/7trjbs New play.
Keep in mind that you're more likely to lose ranks when being low in the rankings (#10,000 can be considered as low in this context) because a lot of people are having a very similar amount of PPs. Hence if only one person beats you on a map, you can lose some PPs and fall in the global rankings.
Obviously a necroed thread.... but still worth posting in.It's possible.
How much pp should a person expect from decay? I think I get -240 like 3 times a day (usually when greatly improve one of my scores). I can't be decaying that fast right?
I think it's kinda stupid that a music game punishes you like this for playing songs that you might like but you can only get C in. Thats like telling you to stop liking music, and focus on the game... Which is kinda usefull but also a little roughWhy dafuq are you necroing such a old thread???