You've knocked out some pretty impressive km's there... Or 800s... Or...
tRicky's correct - it does *look* like 500m times, but actually a little longer.
Fletch is also correct - "Or...."
Somehow every week I've managed to run my "3rd fastest 400" according to Strava, which surprises me as I have felt that if anything I've been easing back on the throttle a bit so I don't over burden myself. I must be hovering around my 3rd fastest 400 and chipping off a few portions of a second each time I do intervals, thereby upgrading 3rd place every run.