求教：降级EB3 Cocurrent Filing485后跳槽有没有必要PP140的问题

请问大家，交了双飞降级，AC21是指485pending 180后可以跳槽，前提是140批过。但是我记得140批过后以后180天内前雇主可以revoke你的140啊，这样的485不是自动失效了么。。因为正常情况485pending了180天140肯定批过不止180天了，但是降级的时候就不一定了呀，大家有没有注意到这个问题呢
如果这个假设成立的话还得等降级的EB3批过后180天跳才最保险，which is很久很久。。。

感谢！回复加mi！

（https://www.uscis.gov/forms/peti ... on-for-alien-worker）

The petitioner may request to withdraw a Form I-140 at any time. However, if the petitioner requests to withdraw a Form I-140 that has already been approved for at least 180 days or if an associated Form I-485 has been pending for at least 180 days, we will not revoke the approved Form I-140 and the beneficiary will retain the priority date from the form. We will consider the job offer withdrawn, but the Form I -140 will remain approved for purposes of INA 204(j) portability unless we revoke it on other grounds. See 8 C.F.R. 205.1(a)(3)(iii)(C) (revised effective January 17, 2017). In order to become a lawful permanent resident based on the continued approval of this Form I-140, the beneficiary must either obtain a new job offer under INA 204(j) or have a new Form I-140 petition filed on his or her behalf.

这段话我的理解是，如果485 pending 180天了，140即使被原雇主withdraw也不会导致140失效，只要是similar job依然可以port。如果有理解错误请大神指出。