This was definitely true for my interview. I found it a bit odd at first, but you have to try to keep up with their pace. If your know your answer is going to be short, just keep it short. An answer and ~3-4 sentences to elaborate should be fine for most of the questions. For the difficult questions, it's okay to pause, even for 5 seconds - take a breath, put a finger to your lip, then answer. The 5 seconds may actually feel like an eternity, but it will make a difference in the quality of your answer. You can practice this a week before the interview to develop a rhythm.