Oh for ****'s sake. Do you have any idea where the whole "17 games" thing came from in the first place? I didn't make it up; I don't even think about stuff like that on my own.
The original story was produced by ESPN or Fox Sports, and chances are they stole it from someone else.
Originally they brought up the point that over the previous 17 games, INCLUDING THE PLAYOFFS/SUPER BOWL, the Chiefs defense had given up an AVERAGE of less than 19 points per game. Look up the definition of AVERAGE yourself. And they're the ones that made note of the fact that some of the point totals were skewed because the defense wasn't even on the field for some of those points.
Then after the second Raiders game and the CAR game, the new story was that the Chiefs had still only given up an AVERAGE of 20.5 points per game.
The only part of the whole thing that I added was that TB was held to a TD less than their season average. And that the Chiefs defense forced TB to go 5-and-out, 3-and-out, 3-and-out, 3-and-out, 3-and out on their first four drives of the game. And that TB scored just 10 points until the fourth quarter. And that TB only scored 4 times on 11 possible possessions. But that's the entirety of my contribution to the story.
You have a problem with the math or the reasoning, take it up with ESPN. But I checked it, and when you exclude points that were scored when the defense wasn't on the field, it adds up. It's about a point lower if you delete points scored in garbage time.