For my case, NC started immediately after I filed 485. The notice date of my 485 is Oct. 8, 2007. The NC started in the mid of Oct. 2007. Same as figure print checking. They both started after you filed I485. You can read pijiang's blog about NC.
I found out those information from Infopass. To be sure, you should schedule an appt with them and ask when they started NC.