Why don't you make an infopass and let them know it is a DV case...It is a long wait for you.
Ok, we are in 2011 and I still did not get an interview letter.
I called USCIS today and was told that my FO-Newark is still processing applications from July 2010. I was also told that it doesn't matter if it's DV Lottery case or any other case and I need to wait until they process all other apps starting July. My FO got my case only in Nov'23.
It feels like it's purposely delayed or something.