What tone curve?
What I'm convinced of is that what we have really isn't RAW. By that I mean something is goofy because when you take photos of a properly lit scene let's say a tree in the shadow, the shadow cutoff is so much more extreme on RAW. No matter how you kick up exposure, Brightrness and it is hard to recover data from the shadows. If you look at the JPG you see detail there and it looks fine. Significantly more data. So what does that mean? As far as i'm concerned RAW on the N900 is really not that much better than JPG and in most cases JPG will give you a better file. As for why your guess is as good as mine.