Just to be clear ... My flight in was YUL-FCO direct ...
My return flight is FCO-BRU-YUL ...
I made a change to a 48 hours stopover in BRU, i paid the change fee and fare change. Now my return is FCO-BRU-<STOP>-FRA-YUL ...
I'm in BRU now ... Can't upgrade FRA-YUL ... Can't pay extra to upgrade my ticket ... That's what I was told by S/E desk ...