I know how experience increase works in Powerplay-Manager. Every day a Player logs in he will get +1 experience for his team. But I have a friend that does not log in everyday. Last time I checked him, he had 151 experience. At this moment he has 149. How did he lose 2 experience points?
Every manager gains experience automatically by playing the game regularly. For each day that you log into your team you gain one point of manager experience. For three days of inactivity you lose a point. Until you get to 11 points you don't lose points for inactivity. Once you reach this mark you will not drop below it.
So, your friend lost 2 experience points because they have not logged into the game for at least 6 days.