Obviously nonsense, so what went wrong? In a first step the unfortunate mix of three different measures for the night sky brightness in the paper - absolute full, absolute artificial increment and relative increment - had to be cleared up which was trivial compared to mastering the formulae to convert between the three different absolute methods in use. That done the paper's key contents could be condensed into this master table which was then - crucially - amended with my own SQM measurements in two Dark Sky Places in Germany and on Rhodes in the past two years.
Since I had been present during these measurements I knew what actual sky appearance they meant - and that finally connected the numbers in my table and in the paper's main table and graphics with the real sky. It turned out that the paper's authors had been way too demanding in what a non-light polluted sky had to be like (and they had also been a bit too conservative re. the visibility of the Milky Way). Using my own experience and their - calibrated better than ever - numbers the article could finally be written after several hours of quite exciting "data journalism" and practical math. You're welcome!