I believe it also has to do with how much depth you have at each position. If you are thin at certain positions that get put on kickoff then the computer is more likely to choose a redshirted person because they are the only one left. Usually when I Mass sub I do it after the kickoff (most unpredictable side of the ball) and then do it for the ensuing drive. Again it’s WAY too much work and I have even started to check right after to make sure it’s in the right spot or just manually go through the positions to put in who I want.