Can someone tell me what fare class "BLSQ" is? I assume it's B, but am not sure.

Also, can SWU's be used for more then one segment? i.e. if i want to go to FRA but there is a stopover in YUL. If I use the SWU at YYZ, will it be applicable for the whole trip (i.e. YYZ-YUL-FRA,- or just YYZ-YUL or YUL-FRA)

TIA