read about this trick some time ago on the Internet but can't remember the source...
from what i remember, the steptronic learns your driving patterns for the first 2000km thereabouts when new or after a reset... the cause of some jerkiness is that the cars are still in the "breaking-in" period for the first 2000km if purchase 1st hand, when the driver is gentle or maybe overly aggressive (hard breaking-in method) with their cars.
So the steptronic remembers and executes the shift patterns from the breaking-in period if it wasn't reset.