I have said it before and I will say it again. SAS is the best airline in * regarding OP upgrades.
I have been on 8 segments SAS longhauls this year and I have recieved OP upgrades on 4 of them. Thats 50%! I can also confirm that I had the cheapest ticket onboard for all those flights.
I was upgrading on BJS-CPH in June so OP upgrades ex Asia works as well.
I would guess summer is better since almost everything is full then(except business class).
BKK/SIN/BJS in Asia is almost 100% full all year.
Not sure if anyone has got an Y award OP upgrade but I dont think they look at the ticket, just on your status.