I disagree with #3. You should post a positive BOI if the transaction goes well, period, rather than holding out like a carrot on a stick.
One pet peeve of mine is when I'm asked "what's the lowest you'll go". NO. Give me the courtesy of making an offer, and then I'll consider it. Unfortunately, when I have actually given an answer to that question, the person almost always comes back with a lower offer - rude much?