From the document I read in detail yesterday, I understand there are three types of security checks done by three different units.
1) IBIS name check by USCIS
2) FP check done by one unit of FBI
3) Name check done by another unit of FBI.
Usually the first one doesn't take long. People don't talk much about this. Second one is done usually on the same day by FBI and results send to USCIS. Third one is little time consuming. It takes a week on average (normal cases) for the FBI unit to report back to USCIS. Once all the three checks are completed, NBC people incorporate those reports into our A# or T# file. If the A# file is ready, those applicants are lucky. NBC will immediately do initial review of the case and decide which documents will be needed for the interview. At the same time they will put that case in the interview queue. That queue system is accessed by the local DO. They open it, approve a date and time as per their schedule. Once the case is approved for interview by local DO, NBC will see that in their system again and then prints the IL with document check list and mail it to us. Once the case is transferred to the local DO, NBC has nothing to do with our case. Their role ends. Then the communication starts between the applicant and local DO. As for the Yellow check list from NBC, it was issued irrespective of how fast this process is moving. If somebody has a speeding ticket and checked YES, they send this generic Yellow list in advance for the applicant to get court documents or other things ready. If A# file is not ready, they put in a request for it and the USCIS guideline says that NBC officers should wait for 3 months trying to locate the A# file and if they don't find it even after 3 months, they can proceed with the T# file available, transfter it to the local DO and finish the process. In my case NBC requested A# file on Oct 4th. That means, either they find it soon (if I am lucky) or they will wait until Jan 4th 2010 before they proceed with interview using my T# file. That is the standard procedure. There are exceptions though. Their file tracking system (NFTS) sometimes show wrong location of the file. So NBC people sometimes see that the A# file is already located the local DO building (even though it was an error) where the interview is to be held and they schedule the interview. IL is issued but the local DO finds later that the A# file location in the NFTS system is wrong and it is somewhere else. That's when we see the interview cancellation and rescheduling letters directly from the local DO. As per the document I read, interviews shall not be scheduled until all the security checks are completed. If an IO says during the interview that they cannot make a decision because they didn't receive the security checks feedback, they could be misleading.
BTW, this is the email reply I got from FBI recently regarding my FP's.
"We received it on 8/25/09 it was completed the same day and sent back. The name check part is done by a diffrent section you can call about it at 202-324-2399 "
In "smartspider" case, they won't even tell that they requested the A# file. That's strange.