Originally Posted by
Fly2Where
That's exactly what it means.
What you referred it's just AA upgrade chart, it also has partner upgrade chart.
https://www.aa.com/i18n/aadvantage-p...r-airlines.jsp
IF you had tried, you will know. under normal circumstances, ie BA ticket (125 ticket stock) booked on AA, you are NOT able to upgrade by AA. (I thought this has been widely discussed, AA can't touch BA stock unless under airport control). And this is very common across all airlines.
The opposite, even if it's NOT operated by AA (ie BA, although it needs to be higher fare bucket, you still able to upgrade on certain BA, IB operated flights).
So your answer is exactly the opposite to the reality.
I don't know, I never tried it, I just go with the published rules here. I am aware of the different airline ticket stock creating issues in other circumstances, but don't have experience with that one.