Not totally sure on this one but I think the following is right for a given race:
- official rating is that which applied at the time the weights for our race were determined
- adjusted rating shows any change to the rating that has been made since the weights were determined but before our race was run. It's therefore going to be the basis for a horse's future rating (with further adjustment to take account of the performance in our race) but it's not the basis for the weight that a horse actually carries in our race.