Yeah the Cup brings an added dimension of managing your player's minutes. Some people just play all their starters in both league games and the Cup game, which will give them like 120 playing minutes, which is a DISASTER for their Game Shape and they will really suck in future weeks due to that. So sometimes you have to bench one or more of your starters in league games if you want to compete in the Cup and not kill your Game Shape. It's usually a good idea to bench some if you play a really weak team (or really good team!).