Exactly the same situation at Alaska when I was there. You could non-rev list using your seniority date. If you listed for the jumpseat you went to the BOTTOM of the non-rev list. Everyone else got on before you would get a seat in the cabin. Your seniority didn't mean squat with a jumpseat listing.

Even then there was an issue. Jumpseat listing didn't take into consideration your seniority either. The only discriminator was AS pilots first, then QX then everyone else. In those catagories it was first come, first served.

Pilots not allowed in the F/A jumpseat except QX pilots on the QX F/A jumpseat.