For I140, the only security check is IBIS check. For I485, besides IBIS, finger print check and name check both done by FBI are required. IBIS and finger print check are very quick, normally less than one day if no critical hit. For most people, the slowest check is name check, which we are always talking about. It is time and labor-consuming if a hit, regardless of minor or critical, shows up. Since it is done by FBI, CIS has no way to accelerate it. But for you, your case is due to the delay of IBIS check. Most people don't have this problem. I think, you might have some kinds of records in customs system or police record or even a record for another people with the same name as you. It is done by CIS itself. So you can push CIS again and again.