Studying Abroad - do they need my high school transcript/diploma?
Yes, German universities oftten require an official copy of your high school certification, even if you already have a university diploma which implies the completion of a high school. The same happened to me when I was starting my PhD in Germany - I also was required to present my high school certificate, although I also had two university diplomas (bachelor and master). In a similar manner, both of my university diplomas were required.