[KenWittlief]

I dont understand how putting a deadband around 127 will make the joystick less sensitive

in fact, your bot is going to lurch when the joystick is moved just outside the deadband

dividing the joystick variable by two, and then correcting the zero point by adding 64 - makes the full forward or full right... positions of the joystick equal to half forward, or half right... making the entire motion of the joystick less sensitive

and making it easier to make fine control adjustments to the motion of the machine while driving - ie when you want to manuver to capture a ball, or position the robot precisely on the field.