Hi Andi,
du kannst hier nicht einfach deutsch schreiben, du verwirrst die Kollegen ja völlig 
Willkommen jedenfalls 
Back on topic. As you know I have sadly no expertise in HCM and do not understand the context of your question, but since it seems your question is not answered yet, just a short idea: could a code inspection of appropriate transaction give you a clue where the default value comes from?
Viele Grüsse nach Kowelenz