Exploding Torqueflites

Maybe I missed something... If you have a stock valve body, when the shifter is in manual low the L/R band is applied. When the shifter is in automatic low the L/R band is not applied. Right? Then why wouldn't you always want to start in manual low regardless of whether it was a burnout or a launch? If you start a burnout in manual 2nd... the trans is starting in 1st gear non L/R applied. Like I said, maybe I missed something, please help me out here and explain further.