[AW128i]

I think that, like all (?) dual-clutch transmissions, the DCT pre-selects the next gear (up or down) based on many factors. If the pre-selected gear isn't the one that's ultimately requested by the driver (the transmission has predicted an upshift and the driver requests a downshift, for example), there can be a perceptible lag in the shift. I think this is where people start to notice misbehaving shift paddles or laggy transmission behavior, particularly in regards to downshifts. I've owned a couple cars with dual-clutch transmissions and driven many more, including BMWs, and they've all exhibited some of the same behaviors with some worse than others. Just my $.02!