I have some boosts for learning speed up and building speed, etc. as well as extra defense/offense for troops. My question is - when do these take effect? If I try to use them on a process (say building) that has already begun, the stats don't change at all. The same amount of time remains. Same for knowledge time. 

Do you have to apply these boosts BEFORE you start building, etc for them to work? I am just not seeing any advantage at all for using these.