how to estimate times within a video: a) be an experienced speaker who knows consistent pacing. b) read it out loud in advance (as one always does) and make notes of the time for full length and possibly the point where you mention the time. c) record straight into the editor or set a stopwatch so you can adjust the current time you say on the fly. d) utilize pre-laps and end screens to make tiny adjustments to get it bang on. it's not a hard thing to do if you know your trade (which tom does), but it IS a very clever add to a video about being unable to estimate progress bars. :)