Having some experience with routes like this, I would guess that the .bomb might see this as SEA-ORD-BDL-IAD in one direction and IAD-SFO in the other. If it sees it that way, you kinda get an extra upgraded flight using 5 e500s on the outbound, but that's nothing to write home about.

Sometimes I think .bomb gets confused and thinks the "turn" in quick-turn/same-day round-trips or open-jaws is in the airport with the longest connection time, regardless of the actual O&D fare booked.

So depending on connection times this trip might also be seen as SEA-ORD and ORD-BDL-IAD-SFO, in which case you would get great usage out of 4 e500s.

Highly doubt it will be seen as essentially a single direction SEA-SFO.