If I was a bad dart player throwing darts at a very long timeline where there were regular marks every 10 inches, I'd expect half of the darts to end up closer to the right mark and half the darts to end up closer to the left mark.
In this case the marks aren't evenly spaced, but I have trouble seeing why that matters over a long timespan since the intervals average out to once per 10 minutes.
Sometimes the blocks can take more than one hour to solve (so we aren't just talking about those getting solved quicker).
The average is 10 minutes but there can be quite a bit of variance.