I just spoke to a WP rep, sine my EWT-DTW and DTW-LAX flights did not credit from Aug. 12. She said that NW has switched over to a new system which attempts to verify the various details of a flight (e.g., class of service paid for vs. flown), rather than simply posting the flights automatically. The agent also said that it will, from now on, take WP mileage about 2-3 weeks to post.