so my I-140 was approved on 8/2 at TSC. Last week, on 9/7 I finally got the receipt for my I-485 from NSC and the LUD now for this case is 9/9/06. When I checked online now my LUD for my I-140 now changed to 9/13/06. Could this mean that they're starting to work on my I-485, meaning, they went and checked to make sure my I-140 was indeed approved? Why else would they be looking into a case already approved??