I'm currently booked in economy (x) YYZ to CPH on Aug 30, and then coming back ZUR to YYZ in economy (x) on Sep 13th. I understand that If I see availability on Aeroplan booking site for Biz or First, I can call and upgrade for $90 plus point differential. Will I have to do that seperately for if I only see avail in one direction? Would I have to pay the $90 again if I see the second leg open up after and another chunk of points?