In the relays 4x1 or the 4x4 you want to have extention when passing the baton.
As well many do not understand that the 4x4 does require a run out as well. You cannot go from standing to grabbing the baton and just sprinting. Yes we know the incoming runner is tired but remember it is their job to get it to you and in your hands.
Unlike the 4x1 I feel there is a lot more chance for you to analyze your runner and how they are running to better judge your initial takeoff and after.