AAO OR USCIS

I filed an I140 appeal last year, and the USCIS LUD showed that they have transfered my case to AAO, and AAO will notify me for any decision. recentily that the USCIS LUD showed that "your I140 IMMIGRANT PETITION FOR ALIEN WORKER was received here for processing. It is taking between 30 and 60 days for us to process this kind of case. We will mail you a decision as soon as processing is complete." I am not sure whether this informtion is form AAO or USCIS? if it is from AAO why it shows on USCIS's website, and also usually it will take 30 to 180 days for AAO review. Otherwise my case go back to USCIS again? I am really confused, who has this experience please help!!