Here's what I see:
Seattle gave up 32 points in 2 games to St. Louis. Washington gave up 31 points in ONE game to St. Louis.
Seattle gave up 12 points to Carolina. Washington gave up 21.
Seattle gave up 7 to Dallas. Washington gave up 31 and 18.
Seattle gave up 20 to Minnesota. Washington gave up 26.
Yet in every game except Carolina, Washington scored more against our common opponents than we did.
Conclusion: Our offense is not as good as theirs. There defense is not as good as ours.
Something to note, however: Carolina is the game we scored more than the Skins did. Carolina is 11th ranked defense per DVOA. St. Louis is ranked 7th HOWEVER, that was week 2 or 3 of the season? No one was ready for the Skins offense and it had initial success surpassing what it did later in the season. So one could make the following conclusion as well: Vs mediocre or crappy defenses, the Skins will rack up more points than the Seahawks. Vs good defenses, however, the Seahawks can outscore the Skins.
The Seahawks aren't playing against a good defense, they're playing against a mediocre defense and should rack up some decent points. The Skins, however, aren't playing against a mediocre defense, they're playing against an ELITE defense. They will be lucky to break 16 points.
That's what I take out of it.