My wife had her oath on June 20, three months after the interview. We had our interview on March 11 and I had my oath on May 16 although the officer told that the oath will be at the same time. So, we went to BCIS office where the interview was held (different from the regular BCIS office in Phoenix, AZ) on Jun 6 and handed a hand written status enquiry letter to the district officer and to our surprise, we got a call in 15 minuites with the news that she is being setup for oth on Jun 20 (???). Anyway, just wanted to share this experience with you waiting for the oath letter for more than 3 months. It may be worthwhile to check the status in person. Thanks