I did CPH-BKK a while back and I got the upgrade via Optiontown from Y-->C for me and the Mrs and we got the points for C. Received the e-mail 3 days before departure. On the return I also signed up for Y-->C but it didn't clear, however I was able to upgrade me and the Mrs to C with points at the gate. C and Y was full, it also puzzled me that SAS didn't rather have my money than points for the C-class seats.