How high above the roof is your antenna? Have you tried adjusting the aim, scanning for channels after each adjustment? Are you aimed into trees or other obstructions when looking toward Queen Anne & Capitol Hill?
Unless your TV tuner gives you the ability to see which of the KCPQ signals it locked on, you don't know if you are seeing the primary signal broadcast on real CH-13 or the translator signal which is broadcast on real CH-22. I expect the CS-4 would do better with real CH-22 than real CH-13.
I'm in the same reception market as you. My personal experience has been that the largest antennas are not over-kill. The ClearStream 4 is enough antenna on based on the report you've posted, but a DB8e or 91XG for UHF and a Y10713 for 9 & 11 (if you want them) is not going to be excessive.
I'm a bit concerned that the PA-18 may overload if you're getting hit with FM from either Tiger or Cougar Mt. The RCA TVPRAMP1R is far more tolerant of stronger signals.
Before you buy anything else, please run this test:
http://forum.tvfool.com/showthread.php?t=13646