In the artist's words:

What are you supposed to do? After 29 years of band history, 5 studio albums, a live album full of their own songs, countless concerts and even more parties for the usual reasons for a "hobby band", they drew a serious line under "one of Germany's best-known ska groups" (Wikipedia) with a final release in 2010.
Then they let themselves be persuaded here and there to play one or two "last" gigs. At some point, they realized that it's even more fun now than it was back then, and that the audience seems to feel the same way. And that the pain of only seeing your band mates occasionally (and practically not seeing the many people you've grown fond of on the road and met again and again over the years) is harder than you thought.
And now? Yet another "very last" concert to ease the phantom pain? What are people supposed to think...? And then you realize that you're already back in the thick of things and it no longer feels like a farewell but like a new start. So let's get going and make sure that the old lady crosses the 29-year mark with dignity.