Flying JNB => CDG on May 1st, booked in PE (A fare bucket). I can book a one-way reward in C for something like 200k miles, but when I call the Platinum Hotline to upgrade the ticket they tell me there's no availability and I should call again in a few weeks. Are upgrades and reward tickets going into different fare buckets? I though it wouldn't matter anymore. Or is it just a HUCA case?