I was reading through to see if OP was understood properly. Sometimes it looked like he was understood but sometime it looks the other way. It was when I saw this question that I was convinced that OP was convinced.
I think having a stat to show if a thread was locked by an author or the mod is important.
To me, if a thread is locked by a moderator at even the first page it will show that the thread is not relevant.
This is different when the OP locks the thread at the first page, we can say that the OP had gotten the answer or the reason he created the post.