I see mentions of the reasonable B fares every once in a while, especially in discussions of US-Europe fares. Indeed, they seem a good deal in terms of saving on the copay, extra points and lower upgrade mileage requirements.

All of my flying on AA is only on US-Japan routes. For a while I played with trying to price a B fare on, for example, DFW-NRT, and the fares seemed excessively high. Was my research flawed or are B fares to and from Japan not that attractive?