It's a feature! I sit with the 1920x1200 laptop up close so I can use the keyboard and have the larger-but-lower-resolution second monitor as far away as it can go. It almost makes up the difference in window size. Why do we claim the OS is "DPI aware" when we are forced to use the same settings for all displays???

That assumes that the test doesn't have a systematic error. If you are systematically biasing the results (and in the case of the lab that did the Tour de France testing, since their procedures and logs aren't published, we'll never know if they are biasing the results), any number of positives is no more remarkable than 1.