I have a 2019 MKC with ACC and it doesn't go to "0" but stops around "10." I understand the 2020 Corsair will have "full range" ACC, like my 2018 Audi Q5.
Interesting... My 2015 MKC has the ACC as you describe stopping arund the 10 MPH mark. But my 2017 MKZ with ACC goes to 0. Although I absolutely hate it below the 10-15 MPH threshold. It brakes must later than I would and then comes to a relatively hard stop. Then when it starts up again, it allows too much time and the cars behind me are already honking because I am not moving!
It is interesting that Lincoln would have the tech in a 3 year old 2017 MKZ (Purchased July 2016) but not in the current model year MKC.
My '17 ACC cancels when it dips below 10MPH. My MKZ loaner did full stop and start and I loved it. Sucks that '17-19 doesn't have that, but I think it may be more than a SW or Forscan programming thing.