By the way - TSSAA soccer refs do not add time for anything. They stop the clock when goals are scored, cautions, red cards, penalty kicks, excessive substitutions, injuries, etc. That way when the official clock alarm goes off the game is over (regardless of where the ball is).
FIFA, however, allows the head official to add time (which is pretty subjective) unless they have a fourth official who keeps track of lost time and then communicates the amount of time to be added to the game to the head official.