Originally Posted by
RedChili
Only partly true. The simple fact is that SAS Plus on short-haul flights is treated as business class by Star Alliance even on paid tickets, with e.g. access to Star Alliance lounges. Also, paid tickets booked in C means seating in SAS Plus, while SAS releases Plus award tickets in I class (Star Alliance business awards).
They release them in I as there only are O, I, and X from a Star Alliance award perspective. Their own Plus awards used to be in F, but it is a long time since I booked a Plus award, so I don't know if the switched to I for SK awards as well.