I don't understand, why do the first ones until point 6 included add up, and the next one multiplies?

Don't they all just multiply? That would get you to to 2987,92%.

I don't think that high number matters if you have a cap at 375%, but if you don't reach it, it is important to know how to compute the bonus, which I think is by multiplying each figure.

E.g., when I have weekly bonus + stamina bonus, I get 225% if I remember correctly, which comes from 50% x 50%.

I think it would be good to have the right formulas in the main posts for clarity.