I share James' question. I initially thought the difference must be as Jim describes, but the more I looked at examples the more they all seemed to be the same. In fact, the future anterior seemed to me to be an unnecessary complication of a pretty straightforward situation. The Future/Future examples just sound better to me than the Future Anterior/Future. When an answer will have been offered, I will understand fully. (Doesn't sound any better in English)!
Many thanks, Jamie