Bit of a long shot this, possibly even a dumb question...
I'm paying for an economy to business class upgrade using OnePass miles on one segment of a connecting flight (I don't have enough for both legs). Is there any increase in the possibility of getting upgraded on the other leg, just because of being in biz class on one leg? FWIW it's a GIG-GRU-EWR flight and an EWR-LGW flight, connecting same day. If so, which should I pay for - 1st or 2nd leg?