I think davidd that you are failing to understand what you do not want to understand ? It is hard to understand why a 19,000 hour US pilot (that is around 32 years of full time flying by the way !) would be seeking a UK medical. However the standard is not designed for such an exceptional case. The standard is designed to satisfy the requirement in the relevant jurisdiction.
It is not simply a case of failing the initial test that results in disqualification, since there is further testing that can be submitted to, and if the apparant CVD applicant wishes to progress, has to be submitted to.