However, in the event of a last minute equipment downgauge and there are not sufficient # of J seats, the P25K will be the first to be bumped, notwithstanding that he/she has bought a Latitude ticket and confirmed the upgrade months in advance. SE on a Flex ticket who managed to upgrade during the window will get the seat first.

Compare shop. Very often, one will find nominal difference in price between AC's Latitude fare and other airlines' "First". One will know for sure to be flying in the "premium cabin" plus the benefit of extra COS. It's better than booking AC Latitude to upgrade to avoid the above type of situation unless one is using a FP.