Anything Goes : Question-Saved by the Bell by Kevin Hager

When Saved by the Bell first started it was the sitcom Good Morning Miss. Bliss, with Mark-Paul Gosselaar as Zack Morris, Dustin Diamond as Screech Powers, Lark Voorhies as Lisa Turtle, Dennis Haskins as Richard Belding, and with Max Battimo as Mikey Gonzalez, Heather Hopper as Nikki Coleman and Hayley Mills as Carrie Bliss. But didn't do so well, and the series was retooled as Saved by the Bell, Max, Nikki, and Mills and their characters were dropped and new ones took their places: Tiffani Amber-Thiessen as Kelly Kapowski, Elizabeth Berkley as Jessie Spano, and Mario Lopez as A.S. Slater. But the Good Morning Miss. Bliss episodes were added to SBTB as earlier episodes, how did that happen?