There's a fundamental difference between flawed values and ideas, and flawed interpretations. While one might argue with the statement in Revelation 22:18-19:
"I warn every one who hears the words of the prophecy of this book: if any one adds to them, God will add to him the plagues described in this book, and if any one takes away from the words of the book of this prophecy, God will take away his share in the tree of life and in the holy city, which are described in this book."
I believe this passage is simply referring to the idea of alterations to the Bible's main ideas. God knew that humans wouldn't be able to perfectly record every detail as he dictated it, or in the case of the letters of the New Testament, inspired it. If the Crusaders had stuck, "and God declared 'Go out and kill the infidels'" somewhere into the Bible to justify what they were doing, that would be what the passage is referring to. Anything else, the flawed interpretations due to the fact that humans were recording (note I say recording, not writing. Humans only wrote what God either told them to write, in the case of say the Ten Commandments, or what they were inspired to write by the Holy Spirit. Either way, nothing in the Bible was written without God.) the Bible, there are bound to be flaws of the interpretation kind. Even translating from one language to another is bound to cause small changes. If you translate "The spirit is willing but the flesh is weak" directly into Russian and back without taking any liberty in the translation, and you end up with something like, "The vodka is arranged but the meat is rotten." Yet, God said to spread the Word to all nations. Therefore, one can conclude that he wasn't concerned about small discrepencies, so long as the important messages stay the same. God created, Man fell, Jesus redeemed, the Holy Spirit empowers us to carry out God's will.