Hi,
with a 10-year fixed interest period and an initial repayment rate of 1%, you have a very high interest rate risk after 10 years. €620 is not enough either, it's more like ~€650.
After 10 years, i.e. when the fixed interest period expires, you have an outstanding debt of €178,000. If the interest rate rises by 2%, your follow-up financing installment will be €950, at 4% €1250.