I can also contribute something about special repayments. I structured my financing similarly to the OP’s, of course with significantly lower figures, and planned to make roughly €55,000 in special repayments over 10 years so that after those 10 years no additional financing would be necessary. €55,000 is of course peanuts here. I am now in the 3rd year of the financing and have so far made €5,000 in special repayments. Very sobering. However, I have roughly saved €25,000, so I am relatively on track in a way. But the money is sitting in the account and has not gone into special repayments. Actually, I am saving for a dream that I had to bury for the time being because of the house construction since all my equity went into it. Now I am saving like crazy every month and could fulfill that dream in a few months. But my conscience does not allow it since I “actually” wanted to make the special repayments. Certainly a luxury problem, but for me a big dilemma. Regarding the OP’s financing, I can only say that those figures make me feel sick. Still, I think that if the special repayments are consistently made year after year, the whole structure can work. For special repayments see my text above.