So, just spoke with the lady and clarified everything, and it’s almost as I suspected.
Modules II and III are both building savings contracts – so the installments would generally have to be increased after 15 years in order to be finished within 30 years in total.
However, with both modules, after 15 years you get an option for 2.35%, which of course you don’t have to take if it generally gets cheaper then. They are only split up because Module II still has the better interest rate of 1.35%, due to the cooperation with the house company, which is not the regular branch interest rate.
Now I just have to do the calculations again. If you don’t repay directly with both, but only save, then you pay more interest in those 15 years because the total amount doesn’t decrease, meaning more remains outstanding, compared to if repayment were made directly, right?
Then it maybe doesn’t sound so good anymore, and that’s also what is criticized about a building savings contract? On the other hand, secured interest rates of max. 2.35% for 30 years isn’t a bad rate either.
How do you evaluate this "new" information?