Slick is a default mode, meaning that apart from adjusting the Damping (rebound and compression), Slick mode is fixed as is.
User Mode on the other hand is totally customisable.
What DDC setting are you using (Sport, Race or Slick) within User Mode, and is this for road or track use?
DDC in Sport is most complaint, Race is firmer and Slick offers the greatest support.
For road use, in User Mode, I like the DDC in Sport.
Within any of these sub modes, the DDC rebound and compression settings can be adjusted to suit within the "Setup" menu, then the set up DDC sub menu