I booked an international itinerary today - AAA-BBB domestic, 23h layover, BBB-CCC-DDD international where CCC-DDD is just an interline partner, then the return is CCC-EEE international, 11hr layover, EEE-BBB-AAA domestic.
I had to book the return that way to get a really low price but will probably SDC out the long layover and the BBB later.
Anyway, I then went to apply a miles upgrade and it said “copay: waived” which I thought was odd but nice b/c it would’ve been $1200.
The upgrade didn’t apply to AAA-BBB on the way out, nor BBB-AAA on the return, I suspect bc the long layovers, so I took a risk and called in. I was prepared for them to see that I hadn’t paid and question it - and they did - but I said the system said it was waived, and they didn’t seem to mind that and applied the upgrade to the segments that didn’t get it, which was nice.
After, I tried to upgrade another itinerary with miles but that did ask for the copay.
Is there any circumstance in which the copay is supposed to be waived, or did I just luck out (a lot)?