The forward motion idea is very interesting. I wonder how it plays out in a student's mind. A main issue with regular grading is that a lot of students end up caring more about the grade and their performance rather than what they are learning. It sounds like the forward-motion model is a better representation of the learning process. Dropping from an A to a B doesn't cause you to lose what you have learned, while being up 10,000 XP points (B) instead of 12,000 XP (A) is still up 10,000. Is this differentiator enough to take focus off the grade and cause more students to focus on learning?

I guess an important question could be: What would the feedback from a teacher mean to a 10,000 XP student who is desiring an extra 2,000 XP?