Generally speaking, I use the old adage that if it is airborne on time then it was on time, ie: I work at MAN.. If one of my aircraft is say parked up on the 50's in T3, those stands are basically at the threshold of 25R, so they tend to have more play with the ATD than say something parked up on T2 or remote as we have a standard 20 minutes taxy time at MAN to "play" with.