My guess is this is how the Temporal Frequency Analysis (TFFT) is to be done. You can graph data on an algorithmic scale or on a linear scale. If the TFFT was done on a logarithmic scale, the text would show up rather distorted/compressed/unreadable. I saw someone post the images with a logarithmic scale, not sure where.
My 2 cents...
Awesome work Shizzire! I'm sure Linear not Algorithmic was the clue telling us to use a direct number=letter substitution sequence and not a cipher. Which you proved when you found the first line of the 4th quadrant was NGHIJLMNQUVWXZKRYPTOSABCDEFGHIJL and used the number sequence to get USENETDRAGONSBREATH.
This whole time I was putting the names Marie Curie, Heinrich Hertz, Alan Shepard and Dan Rather, together in different orders trying to use the number sequence to get the letters. Never occured to me to use the 4th quadrant of Kryptos. Awesome!