In our middle school that kind of schedule meant the same classes met very day, but a different period every day. There was an A schedule, B schedule, etc. One reason for it was so that you didn't always have, for example, math at the end of the day or French right after lunch. The thinking was that if you are tired at the end of the day and math is a difficult for you, you wouldn't always be facing it when you're tired.
Our high school is considering implementing this kind of schedule, actually more of a block schedule. I don't know what that would do to the math class that 8th graders can take there. But honestly, I think they would work it out.