In the article using NSC as example, it's a longer wait for I-485. So the faster I-140 will also need to pause and wait for the I-485 processing time.
AC21 protability will be questioned, even denied, if I-140 is not approved before you have changed job. (No matter how long I-485 has been pending)
AC21 protability will be questioned, even denied, if I-140 is not approved before you have changed job. (No matter how long I-485 has been pending)