Uhm. In order for the numbers (debt at the end of the interest fixation period and term) to match up with the annuity loan, the monthly installment must not be €1096, but about €1350, which increases the monthly installment by about €250.
This would mean that one would also be around the nearly €2000 that one would need with the building savings product.
Quickly calculated with an online repayment calculator assuming the interest rate stays the same and no special repayments:
Annuity loan: 123,680 (Sparda) + 6,873 (consumer credit) + 55,044 (KFW repayment phase) + 3,800 (KFW year 1) = €189,400 interest. Roughly.
(With the €1096 repayment rate we would be at €222,050 interest. Roughly.)
Building savings construct:
Much harder to calculate!
15,379 (building savings contract) + €2,400 (building savings contract fee) + approx. €31,500 (L-Bank until maturity of building savings loan) + 196,249 (main loan) = €245,528
I am not quite sure about some of the given values either. Overall, however, it seems to confirm the impression: annuity loans have shorter terms with similar monthly installments, or lower installments with comparable terms.
However, the calculation is not quite clean: with the building savings construct there is more money at the allocation maturity of the building savings contract than would actually be expected with regard to repaying the secondary credit, and at the same time too little with regard to repaying the main loan. That doesn’t make sense to me at first; unless it is intended for special repayments or necessary maintenance costs.
It would first have to be clear how that is supposed to work in order to calculate properly. This is overwhelming me right now, sorry.