How can Southern Rail charge two prices for the same journey?

The train operator sells fares for £23.10 and £16.20 – but doesn’t steer buyers to the cheapest oneFor some time Southern Railway has offered off-peak day-return tickets from Christ’s Hospital (near Horsham, West Sussex) to London Victoria for £23.10, alongside a super off-peak for just £16.20, on Saturdays and Sundays with no time restrictions on either. Many passengers who don’t travel regularly could be unaware of the cheaper deal. It must all a