Correct. Did it mid March.
I do have had tricky times with SDC lately. E.g., changing a MIA-JFK to a MIA-LGA when both were sold out, and I could not do SDS for the LGA flight but they were able to do SDC (win). At another time I could not do a FLL-JFK to FLL-LGA because it was sold out (and overbooked), but I could do a PBI-LGA (instead of FLL-JFK), which had 1 Y seat open (fare class Y, I was in K).