There is no answer for this question.

Some people got 45 days letter in Dec 2005 and their case has been approved. Other people got 45 days letter in Jan or Feb 2005 whose case still not approved. Some people had a PD in 2005 whose case is approved. Others have PD in 2001 whose case still not approved.
Who knows how they work there in BEC, speciall the Philadelphia one.