* The relative success of comprehensives compared with grammar schools in the KS4 value-added tables does nothing to prove that they are better. The best you can say is that they have recovered the ground lost in KS3.
However, there is a bigger factor operating to the grammars' disadvantage.
The best a pupil can hope to get is an A*, so success at KS3 automatically limits their KS4 improvement. Furthermore, an A* at GCSE corresponds to a B at GCE, which was good, but hardly exceptional. There is no reason to suppose that present-day grammar schools could not educate their pupils to these standards if we had an exam system that could demonstrate it.
64 Spring Grove