Update
Based on the information I received from various 'sources', I have concluded that:
1) Security check during I-140 involves the background check for both the petitioner and the beneficiary.
2) Security check constitutes name check(FBI background check), fingerprint check, IBIS check, petitioner's ability to pay.
3) All applications go through security check. Any application could be flagged for whatever additional information.
4) USCIS will not provide a timline to process cases that are under security check.
My case has been pending since 22nd Dec' 2003. There was no change in LUD until 3/10/2006. And then there was another change in LUD on 6/10/2006. I did not see any change in the message though.
I now need to apply for my 8th year extension(H1). I have applied and received approvals for 3 EADs and 3 APs. 2nd fingerprinting has been completed.
My attorney said that they would submit another inquiry through AILA within the next couple of weeks. I had previously initiated an inquiry last October. Recieved a letter from USCIS stating that the case is under security check and they have no timeline for such cases.
My plan of action is now to initiate an inquiry through AILA and if that's not successful, file a case against USCIS. What have I got to lose? At the most, I'll have to leave the country for a year. No big deal. I have grown a thick skin and I have mentally prepared myself for that.