OK, how many high school tracks are completely accurate? My guess is that only 80-90% of them are. I've actually measured tracks, and a few of them aren't 400m in circumference. One was only 379 meters around in lane 1, but meets on that track were still using the 379 mark as the starting section for the 400. No wonder most people were running PR's on it.
Other tracks are too long (410 meters), but the short tracks are more common than the long ones.