Your case is very very normal.
大多數在當時辦PERM的人那樣趕在2005年10月1日排期大倒退前同時遞上I140和I485 is not ture. As far as I know, many perm applicants took around half year to get approved. You got audit, right? When the perm just started, the system was still under testing, so a lot of cases (around half, from labor department official report) got audit. Half year was a a common time period for your guys.
You may find people who got GC approved on this frum, most are NIW.