Why did Martin Luther's account of his break with the Church change between 1517 and 1535?

In 1517, when Martin Luther posted his Ninety-five Theses, he was a remarkably ignorant (for a professor of theology) man who was accusing the Church of things that it never believe in, or asking why they didn't believe in things, which, in reality, they already believed in. In 1535, he wrote his second commentary on Galatians in which he tried to prove and explain his "justification by faith alone" in which he asserts that Christ doesn't really changethe person, so much as He imputes righteousness to him. In other Words, he is not arguing against the Catholic Church so much in 1535 as he is trying to explain his own ridiculous notions of salvation that he made up out of thin air, completely repudiating 1,500 years of Church teaching back to Christ's revelation to His Church. See links below: