Originally Posted by
hhdl
I had a BOS-SFO-BOS round trip where originally BOS-SFO was Y and SFO-BOS was C+ (not booked by me). I bought upgrades separately to C+ westbound and a couple of weeks later to F eastbound. No bonus MQM (even though each direction was upgraded atomically).
Correct. In order to get bonus you must be able to select "upgrade all segments." If this isnt available (and it isnt when you're in different cabins per segment) then you're not buying up to a F fare, simply paying a seat fee.