Although the show's format implied an average of ten countdown songs per hour (once the show had gone to a four-hour format), this was not rigidly enforced; however, by the mid-1980s, it had become increasingly rare for the final hour of the show to have any more than the top eleven or any fewer than the top nine songs left to play. The songs' run times determined how many would comfortably fit into each hour. The show bent to fit the "Billboard" rankings, and some songs had to be edited (in addition to whatever edits had been done for the single release), with a verse or chorus cut (usually for songs on their way out of the countdown), in order to fit into the show. But Kasem and his producers never lost sight of the stations carrying their show, and that the stories behind the songs were the chief reason that listeners tuned to "AT40".