lilypad Unless your teacher wants you to practice the whole piece everyday, the Molly method means you can work on just a section of a piece. On rest days for that section, you can work on another section of the same piece, satisfying the expectation to work on that piece every day.
I interpret her approach to be that the idea is that one works on one section of the piece at a time, but it would certainly be fine to work on more of the piece. Just not together. So maybe you're working on four measures from the A theme. So that's one part of your practice focus. Then you might switch to 6 measures from the B theme. I think that would be fine, but the point is to avoid mindless "playing through," and avoid playing the whole piece before ready.
At least that's my understanding... As I said somewhere (I think I said...) I'm about halfway through the book, but I also started reading the Inner Game again. Maybe I'm mixing things up...