It should be "Receipt Date" - 回复：180-day period will begin from

whenever "Filed" is referred to per my understanding, although USCIS itself may present different interpretations in its same document (like recent FAQ).

The point of 天平上的猫 does put you in a safer position.


Discussion in decent language is helpful, and appreciated. However, it is inappropriate to discourage people from helping each other here in this forum.