A tip that is mandatory part of the regular bill and is even printed on the bill, is no tip. The practice is uncommon, if not unknown in German bars and restaurants. I would not tolerate such places myself, and never go there again. I have heard that staff depends on these payments in America due to their employer paying them so badly by norm. And that is where the problem lies hen: unhealthy business practices and the cost of the employed staff. Fair wages for fair work, that must be the formula.
The few occasions where I go to a restaurant (in Germany) anymore, I base the tip on performance, how I was treated, and the situation in general. I am more generous when I liked the stay. I give nothing when I am pissed. Usually it ends with rounding up generously. But roughly 15% is the utmost maximum. Heck, lets' leave it in relation!
Not that I go into restaurants that much anymore.
