They stated that they use the same calculation for the logs as for other purposes such as latency compensation. From near the top of the blog post:

"The reason we did not find it sooner is that the cause of the issue was a code bug that miscalculated latency, which meant that the values in our logs were also wrong."

And from later in the post:

"Our logs were not displaying the issue because the calculation was wrong. It explained why the latency was worse in the venue than on the internet servers"