my two cents on "official processing times..."
i think they want to take advantage of the regulation that only those applicants, whose receipt dates are X no. of days (i think 120 days) earlier than the official backlog date should call to inquire after their case. hence by keeping the official backlog date well back, they ensure there is a minimum number of people whose official inquiries they will have to respond to. also, they can tell a senator's office that they are still processing cases earlier to the one they are calling about.
bottom line: don't pay too much heed to "official processing dates". this forum and rupnet provide more reliable information.