I disagree. They don't really go into why they made these decisions, but just "oh, our old model had weird sized differences between payouts of adjacent places." Why did it take them 6 years, a bunch of smart people, and hundreds or thousands of man-hours to use a second degree polynomial (constant second derivative) to determine payouts? I'm sure they dealt with more complicated problems than just figuring out an equation with a constant second derivative, but they don't really address that in this article.