Forgive me jumping into this thread, but I found the following information from the NFER web site which might explain why it's possible to have so many candidates with scores of close to 140 following Age Standardisation:-
Two of the main outcome measures of some of the tests that we construct are the ‘national standardised score’ and the related ‘percentile rank’. These normreferenced measures relate the performance of an individual pupil to that of the population of the country as a whole. Tables that give such comparative data are derived from a national standardisation, which usually involves administering the final version of the test, prior to publication, to a large nationally representative sample.
ie it seems that some 11+ exams tests (including Kent 11+ exams) are not always Age Standardised against the exam Candidate population taking the test but against an assumed theoretical national population of child candidates.
I'm hoping perhaps that a statistician or someone with actuarial training may be able to confirm this.
I may be wrong but it would explain why there are so many high scores with relatively lower raw scores. I think the same may apply to Warwickshire 11+ as well where the pass scores were similarly high than one would expect.