I only skimmed this, but it seems like they're not measuring latency at all. They're measuring the time for each item in the queue to be worked on, and then sum

I only skimmed this, but it seems like they're not measuring latency at all. They're measuring the time for each item in the queue to be worked on, and then summing all of those times, which is quadratic if latency increases linearly. Now, I only skimmed this, but I do feel comfortable condemning it based on what I gleaned from skimming.