Yeah pretty much Chris. If it's not an all day concert fest, most of the show times start at 7pm and the main band will usually take the stage around 9/9:30pm. If they play a 2 hour set (including an intermission) they're usually wrapping up between 11pm and Midnight.
Seattle has had a curfew since the 70's. The track was built in the 50's when there were no homes close by. Homes were built close by and the complaints started. They have a certain small number of allowed night events that I believe have to stop by 9pm. Unfortunately they do not use that quota for the Northwest Nationals anymore. The single huge light behind the starting line (that was state of the art in the mid 70's) can no longer light the top end enough for today's fuel cars. I wish they would rent portable lights like Indy & Pomona do, and bring back Friday night qualifying. That would be a huge bonus for that event. They also have curfew times of I believe 5:30 on some days. I still remember Steve Evans in 1971 saying on the PA that Don Prudhomme's second burnout in the final round may result in them having to pull the plug because they were seconds away from the 5:30 curfew. FYI - Seattle has something even worse than a curfew : They have to have a certain number of "Quiet Weekends" where there is no noise coming from the (multi-purpose) track ! This must make it very difficult for the track to make a profit every year. I have heard that they do lots of other stuff with the community to try to make them happy. Thanks to the Fiorito family that owns it, they continue to operate, despite the challenges.