Are upgrades charged per segment?
I'm sorry if this already has been asked, I couldn't find it when searching. I also wrote the Helpdesk, but the answer they gave me didn't make things clearer. My question is simple though, due to bringing extra weight I thought I would upgrade to C on my trip HEL-AMS-VIE, but not on the return. How many miles will this cost me? 10000 for HEL-VIE, or 20000 for HEL-AMS, AMS-VIE?
Any experiences?