Originally Posted by
aacharya
This is extensively covered in the expert.mode thread. And why we all look for upgrades by segment as that's how it will clear.
Rare exceptions for married segments <another thread>.
The OP is saying the opposite -- looking by segement doens't work.
MNL (XXX) - TPE (AAA) - SFO (BBB) shows PZ9 on the AAA-BBB leg.
Searching TPE (AAA) - SFO (BBB) shows PZ0.
If true, this makes searching for the elusive upgrade that much harder, since you can't trust the individual leg inventory, either.
I have never seen this, but got a hint of how it may happen once: Searching LAX-SFO-NRT showed ...Z9P9, but searching SFO-NRT shows ....Z9P0. In this case, i was wondering if the connection would ever show an upgrade available (it didn't), and if it did, what would the direct flight show? I've never seen Z9P0PN>0, so I would assume it would not show the availability.
So, my strong guess is that the P fare is not filed on UA from TPE-SFO, while it is MNL-TPE-SFO, or they are restricting P inventory out of TPE directly, which creates a false negative in the upgrade inventory.