Originally Posted by
geronimo
^^ Agreed. My (anecdotal) experience is that BA marketed tickets are often limited to the rear portion of the business cabin, irrespective of date of purchase relative to date of travel, and seemingly empty seats elsewhere. Occasionally, I can re-assign my seat online at some point before departure. I wouldn't use the call centres of BA or JAL. Nothing to be gained there, as you've already discovered.
FYI nowhere does the OP state that they are traveling in business. But your point still stands...