Financing plan: high equity / 2.67% / 15 years / full repayment

Nope, :p but it's always worth trying to ask. Every day a crazy person gets up :D:D

From when it is probably worth paying a prepayment penalty and refinancing at a lower interest rate....

There are various prepayment calculators on the internet. ;)

It is usually worthwhile when the remaining term of the loan to be redeemed is still short while simultaneously securing a new long fixed interest period. Everyone can roughly determine the break-even point themselves using the online calculator.