He's saying that when it is first spun, the odds are low because of the weighting explained earlier. After that it is not re-spun and is instead advanced to the

He's saying that when it is first spun, the odds are low because of the weighting explained earlier. After that it is not re-spun and is instead advanced to the next bullet, which does change it, because you now are limiting the number of total possible places for the bullet.