I was going to wait until day start to clear this up, but I see no harm in doing so now. Since the boost is tied to my masonry, everything's lumped into the one description, and it took me a few reads to fully get it.
Basically, since it lasts the entire following day and night phase, it's technically an every other night thing if it works and if I decide not to give them a boost. If I don't mason with anyone on the night that I try (like N1), I can try again the next night. Boosting someone takes hold on the night that the masonry ends, and that tacks on an extra night that I have to wait. So, yes, boosting FRAYDO was my N3 action.
So, in a nutshell:
N1-Masonry Begins
N2-Masonry Ends, No Boost
N3-New Masonry
Or
N1-Masonry Begins
N2-Masonry Ends, Boost Applied
N3-Cooldown
N4-New Masonry