I booked mine in and out of BER 6 months ago, so can't help you on that.
Do keep in mind that the German trains are absolutely broken beyond belief so build in large time tolerances to any journey you book.
Most of the English(and other nations fans)have been stunned at how bad they are, even those that rely on Avanti on a regular basis!
You ask any German about Deutsche Bahn and they just shake their heads and roll their eyes.