NC's done or not? I think,

when we call uscis, a lady does check our status, like name checking. that is for sure. Let's imagine, if nc's pending is true, there is no way for her to say that your nc has been done. but why when you call back again, you may get totally different answer. This is my guess: they don't like to see people call them again and again, and sometimes they feel so bored so they just freak you out. So my answer is, for this situation, your name check has been done. Just trust the first answer you get.