Originally Posted by
nshep
I'm super confused because my understanding was any BA premium economy ticket was eligible for upgrade.
That's the point: any BA bucket is, but for selected partners (AA, IB) only full fare buckets are, and for other partners no upgrade with avios at all. Incidentally, even BA metal (but AA or IB etc coded) would be the same In other words, if you want to upgrade, book BA code and metal.