They do based on availability. If premium is full, its unlikely.
If its a west coast route, i'd expect $400-$600 for Y to W. If it is east coast, i'd expect half that.
It all varies a lot to be honest. I have had some very good offers and some very bad ones. Theres no exact science to it really - at least not outside VS revenue management. I am usually trying to do W > J but the same principle applies.
Good luck.