Usually the bulk of activity is happening on Wed and Thur, at least the updating of the online system. Even if they update let's say on Wed Dec 8, the message will be "... on dec 6th ..." . I noticed that happening at least for my date (7/22/2003), by dayly scanning, no change on 6,7 and on 8th the message with the modification on 6th .. so I don't think that they update immediately after they do something ... that might be true only for LUD.