Matheusantaanna

Hi, I'm in need help my ms is not working. I say this because I always trained at cerulean cave and im used to how much I gain xp. For example I get a low level pokemon then I change to one of lv 100 and defeat. I always wins between 6 thousand to 8 thousand depending on the pokemon but never 4 thousand and that's what I'm winning. I am clearly earning half of what I should earn! pls help.