Reply to Traktor Synced Tempochange?

Hey there,

I want to change the tempo in Traktor for 2 decks simultaneously while they are running. So I mapped a button for tempo increase to both decks, as well as for decreasing the tempo. But when I change the tempo, the sync function gets deactivated automatically. Also the tempochange is different on both decks -.-

Is there a way to keep the tracks in sync while I'm changing the tempo, or to change the tempo of both decks with the same value?