Well, I doubt they'd do that. Having worked with Germans, I find it difficult to believe that these numbers would be very easily conned by changing how statistics is done.
I am also quite sure that there are various different unemployment numbers calculated by German statistics officials, but the media may wish to stick something simple, which is probably the one that is also comparable across OECD countries.
Here in Germany, there's just one unemployment number, and its measurement is adjusted some time to time. So in theory, you could have a raising unemployment rate but decreasing official numbers, just by adjusting the definition from year to year.
And in practice, nobody doubts that our government does exactly that. It's really sad.