I remember it being cheaper than most, so that's probably right, at least as of last year. Haven't been there this year yet - I will be in 2 months though!
We enjoyed a fantastic lunch there two weeks ago! My toddler son loved the band! The price seems about right, however, unlike most buffets, drinks are not included! It was much higher once our beer was added... when in Rome, er, Germany...
We had a blast and will definitely do it again! Be forewarned that if you do not fill a family style table with your group, other diners will be seated with you. It's a great way to meet other visitors! Don't be shy, you'll be toasting together in no time!