See, this is wrong. As a passenger, you are not supposed to know all this stuff and request specific booking classes. I learned about fares throughout many years of flying but other people have no clue and are not interested at all. Agents should be properly trained and BA booking systems should be properly programmed. Because often what you hear is the computer knows better and always offers teh cheapest option. When you present the fares rules and tell them it should work they a) ask where and how were you able to get them; b) refuse to accept the rules from Expertflyer: c) are reluctant/do not know how to pull up complete fare rules from their system; d) are surprised why it was not working automatically after they pulled up the complete fares, read them and then agree that it should have worked...