I think at least part of your issue is that you are looking for a one-way fare between DBV
and SEA. If you don't know it, one-way fares on international flights are generally not
50% of the roundtrip fare.
I can see a RT in biz between Seattle and Dubrovnik on Finnair is around $4300. The
one-way is $6000. You can't book a RT and then throw away the originating flight; the airline
will cancel the whole thing.
You have some options:
- cancel the one-way into Gdansk and find a RT or open-jaw across the ocean on Finnair and then
book a one-way intra-Europe flight to get to your final destination
- use miles to book the return flight. No guarantee it will be cheap, but it will be a different
currency and thus possibly a better value.
Finnair is moving to Avios as their frequent flyer currency in January. If you have Avios, or
points that can be converted into Avios, you might want to wait until the conversion happens
and see what you can book. AA miles sometimes work, but not always.
You also could look into Condor. A one-way PE ticket on 10/5 can be had for ~$1000.