Originally Posted by
ernestnywang
If there's 1 QR (or QF, I think) segment, and the plating carrier does collect YQ on behalf of QR, the plating carrier (doesn't have to be QR) will add YQ based on the entire itinerary, not just on the QR segment. In another word, either you don't have any QR segment, or you have as many as you can.
To back this up: I've experienced this and it's important as this one time bump is something like 200 USD IIRC, a fair amount if flying 1 x QR flight but modest if spread across 4+ QR segments. So the "QR has expensive YQ" line I understood before which led me to avoiding QR turned out to be inaccurate when maxing QR on a DONEx. That suits me well as I credit to AA.