[88carrera]

Aerkuld,
You are correct! This past weekend I spoke with a Porsche source whom I trust to have this knowledge and he confirmed what you have said; namely, that the blue VW/Audi factory coolant is compatable with the yellow-green Porsche original factory fill. He said that a few years ago the factory changed to the bright pink coolant that I got at the local Porsche dealership.
Warning, he said that the "old" yellow-green factory fill and the "new" pink coolant are incompatible and may form a gel if you mix them. Not something that is good for a water-cooled Porsche.
So, if you have the original yellow-green factory fill in your car, you can either add some blue VW/Audi blue OR completely drain and flush the coolant and refill with the new pink Porsche coolant. It is probably best to do the latter, just to be safe.
(Dropped into the 40's here today.)