If AC has no Tango fares on a flight, could the LH fare map to Tango?
Looking at $100 saving to take a LH codeshare on a leg YUL-LHR on an itinerary
YTZ-YUL-LHR(stop)-HAM(stop)-FRA-YUL-YTZ
No Tango fares that day YUL-LHR, willing to wait the e-up out to last day but not willing to take Tango and lose an upgrade chance and 2,500 miles for $100. Grrrr why did you do this to us AC?