By saying it can cool to 10C below cabin temp does that not create a so-called infinite feedback loop? ie. cabin is 20C, VCM can cool it to 10C, cabin drops to 19C, VCM can now cool to 9C and so on. I think there must exist a finite limitation in relation to OAT.
In any case its never enough when its hot out...and the 180-day MEL doesn't help either.