180 天从何时算的官方解释, Xiaobaidu, Radiology 好像错了

下面是UCCIS关于AC-21的原文解释:
If the Form I-140 has been approved and the Form I-485 has been filed and
remained unadjudicated for 180 days or more (as measured from the form I-485 receipt
date), the approved Form I-140 will remain valid even if the alien changes jobs or
employers as long as the new offer of employment is in the same or similar occupation.
If the Form I-485 has been pending for less than 180 days, then the approved Form I-
140 shall not remain valid with respect to a new offer of employment.

这里面指出从receipt date算起. 这个日期应该是received date而不是notice date吧? Xiaobaidu, Radiology 好像错了啊?