Comment by proberts

That the I-140 petition is an EB1A petition (which can also be filed by an individual) doesn't change the analysis. If the employer-filed I-140 petition was approved more than 180 days ago even if the I-485 has been pending for less than 180 days, while an employer can withdraw the I-140 petition (thus requiring the employee to get a new approved I-140 petition to get a green card), the individual still would keep his or her priority date.