The definition of "working poor" they use is not "having two or more jobs" but "earning less than 60% of the median".
According to IAB 2.7 million workers have a second job in Germany (which is about 1 in 12). Most of them probably because they don’t earn enough in their first.
Not to forget that this number alone doesn't mean anything, we still need to compare this number to other countries or to the past.
But then we also need to consider stuff like this: AFAIR the number of "working poor" or "relative poor" decreased in/after the crisis 2008.
Why?
Not because companies paid more during the crisis but simply since the median income decreased.
