This is, in effect, a double negative, so it's easy to see why it created confusion. As to the facts - operating speed, operating voltage, and gate switching times, are important, too. This suggests it is just one factor.
Not surprising at all. If you've ever worked in China, you'll know that the tax laws are vague and subject to different interpretation by different officials even in the same tax office. It just isn't black and white.
This is highly relevant to Japan as it is a very cash oriented economy (surprisingly so for an advanced country). Makes sense also for Chona, Brazil and Turkey which are also cash economies (albeit with lower per capita incomes than Japan).