Yes there is anther memo issued sometime in 2009 overturning this one. You
should find it by google. I saw that before. It basically talks that if the
background has not done, the visa can't be granted and, the 2008 memo should
not be used anymore since the NC is much faster at that time. However, if
the FBI NC is delayed by more than 180 days (or 90 days I can't remember
exactly now) the USCIS shall push FBI to fast the process. In addition,
USCIS and FBI target to finish 98% NC within 30 days,