Okay, then we're closer than it seems. My favourite authors are those who, like Chaucer and Twain, write the vernacular, the way people speak. I just think "I thought I replied" contains an assumption about the facts which is not obvious, and an approximation or blurring of times and tenses that makes it an abridged version of "I thought I had replied," rather than simply an equally formed, alternative approach to the same ideas. I think it contains less information, and fails to account for the realities that must in fact be involved. But I think we now see each others' positions.