Yes Renie, I have the same question. I think Melissa is looking into how to most easily find the right fit, and how to manually adjust things if needed. From what I read, the intention is to start at what you know to be the 'grade level', if a child is still getting 100% after a few lessons (don't remember the exact number) moving up is recommended. If they are getting around 50% right, they suggest moving down. I think they said 80% might indicate the best 'zone' for a child/subject. (writing this from memory, so if any corrections are needed, feel free to point them out!) smile
Unfortunately I just plugged in ds' regular grade for language arts and that does seem too low, so waiting to hear more from Mel.