条件144小时免签证过境

你好,
我读到“乘客应持有一个起票确认座位和日期以及第三国或地区的有效签证。”I understand that the country of my departure flight into Shangai has to be different than the country of my arrival flight (leaving) from Shangai, right? Does it apply only to connection flights or also to the original origin & destination flights? Like in my case, I plan to leave and return to Luxembourg, but I will then take connection flights in different country/ies to and out of Shangai. Will I still be eligible?
谢谢确认!