The Advance model was deemed too narrow at the rear seat area to warrant a sun deck seat, it would be suitable for kids only. In the later years we added the reasoning that the Advance/lazer model was our entry level model to the TBX which did get the convertible rear seat. The Legend was built during the WESMAR years and that model was before my convertible rear seat, but I will be restoring one in the spring & plan an designing a convertible rear seat for that model.