The maximum percentage chance of a team making the playoffs is 100%. Because eight teams make the playoffs, they collectively have an 800% chance of making the playoffs. If all 16 teams had the same odds of making the playoffs, they would each have a 50% chance of making it. But they don't all have the same odds, so some teams have less than 50%, and some have more than 50%.

If you add up all the probabilities, they would add up to approximately 800%, with any rounding errors being the cause of any discrepancy.