Well, I'll tell you my story: I had an interview on July 28, 2004. My priority date was March something 2004. I heard almost exact same thing. But not the same. My case was a bit different because the officer said my case was not approved because FBI did not finish the background check. But, he said, it was very probable that the national service did not forward my file to the district office, which happens quite often. But he said he's not sure.
Anyway, I checked the processing date , and figured out that my priority date was before the processing date (somewhere between October and December 2003, don't remember. but definitely earlier than January 2004) at that time. So, I just PRAYED that the national service did not forward my file to the district office; otherwise, that means that I just joined the FBI-Name-Check-Stuck Club like some unfortunate folks, and it's gonna at least a year or two to get a citizenship.
The thing is, I just gave up the hope that I would be sworn in this year. BUT, on September 1, I got the notice, and took an oath on 23!!!! I just applied for my passport through the expedited service.
Well, so it took, about more than a month to get the notice.