I suppose it viewing time as a whole for the video that bumps up the algorithm. I'll admit to be naughty and sometimes skip parts or to the end part way if im getting a bit bored. No wonder most tend to keep it to the 10 minute mark ... At least there is a choice.Apropos of nothing but the reason for the superfluous padding is purely to game the YouTube monetisation algorithm, which "prefers" long form videos.