DSG tries to guess if your next shift will be an up or downshift. If it guesses right it is much quicker than SMG. If it doesn't guess right it takes the same time as SMG. In other words: it is always as good as or better than a SMG/F1/CambioCorsa/e-gear box.

Regarding skiping gears: if you drive on a track sequential up and downshifts are always the best. The only situation I can imagine where you would skip gears is when yo initiate overtaking on a public road.

/fantasma