Probably a misprint. I used to own a dyno that had different conversion factors such as DIN, SAE, JIs and STD. There was never anywhere near that difference in power swithching from all the different ones.
And below is an excerpt from the Porsche '72 to '81 workshop manual.http://forums.pelicanparts.com/uploa...1717688506.jpg

Yes , I now agree , this is a misprint or a translation error about the specific horsepower type
ratings .