<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by keithguy:
Look for a CO SEA-CHI full fare (e.g. Y8) and you'll see the routing. If the routing numbers are the same (in your case Routing 6), then it'll apply to your cheaper fare.
</font>
Great tip, and one I never knew before. Thanks!