The "sport" drive mode (I.e. Throttle mapping - ignore dsg for now) only takes effect if you switch to sport or individual during that drive. Once you switch off and switch on again the throttle mapping reverts to normal even if you are in sport or individual still.
I have individual set to sport drive and eco soundaktor, but if I want a sporty drive then I have to switch to another mode and then back to individual for the sport throttle mapping to actually kick in.
I believe it's done this way to discourage aggressive driving from a cold start?
All of this is anecdotal from my own experience, but there is 100% a big difference in drive when comparing being in individual from start to being in individual after swapping to another mode and back again.