re: Kind of left me hanging on page 72 though...
Yes, it's almost as if that last paragraph was hastily added just before they went to press. It suggests that the original IPCC estimates may have been far too conservative. Or that they feel the new results are still unconfirmed and need to be verified so the authors chose not to emphasize them. Still, April to August is a long time, even given the glacial pace of preparing something for print publication. In context, the previous paragraph does give a clue. The authors had been discussing IPCC mitigation strategies that were formulated before the new results were available.