I should imagine they probably are accurate. If they were all put in by the same driver Id worry but they are all different drivers on different days, in different conditions, and no doubt at different drag strips. For example, a turbo car will run slower on a hot day, whereas a NA car wont be so affected. York always seems to run 2/10 faster for road cars because they have a decent launch strip. Some drivers slip the clutch, others dump it, some are slow starters and make up the remainder of the run with a lot of power, others have slow cars but run good times because they are good drivers with fast gearchanges and knowledge of their cars optimum powerband.
Id be suspicious if they did all make the book times, as that would be rigged for sure.