Yeah it's a matter of timing and security/stability game. To be honest, I didn't consider extra payment as an option for myself, but in current circumstances it

Yeah it's a matter of timing and security/stability game. To be honest, I didn't consider extra payment as an option for myself, but in current circumstances it really makes sense: not a risk-free investment alternative to 8% mortgage :) But when interest rates will go down, it can change. With a tool I just wanted to show numbers - for sure there is more to consider, but it should help to have a insight to bare numbers. Thanks for comment!