Thanks for the explanation. While I understand the reason, and the site was technically correct returning me a "W" fare BE ticket when I searched for "W", this makes it much more difficult to book W in order to apply PP upgrade. In this case selecting the "Requested Fare Class" price gave me Basic Economy, while the normal "Economy" was in "K" or "S" which would require 80 PP. Another problem is that since I specified "W" in the search, the entire booking process did not gave me any warning or indication that this was a BE ticket. I learned to look for Fare basis code only after making the wrong booking the first time.