Decided to do a battery duration check. Launched H and put it in hover at 50 m with occasional movements right and left. Very pleased when with the final battery warning I got to 20 mins duration with the onscreen clock clearly showing 20 mins 12 secs. When I downloaded the files to my editing system it showed a duration of only 11 minutes 25 secs. A further check in UAV toolbox confirmed the timing. I need to repeat this with an actual time elapsed indicator like a stopwatch , But in the meantime has anybody noticed this discrepancy?