So a big fat upvote right after the timer runs out doesn't capture all the curation rewards? I'm sure all the curators and guilds using that principle to gain financial rewards will be surprised to hear it.

I'm not much of a curator, and I could be wrong I suppose. I just upvote what I want to encourage. Doesn't pay much, and it won't after HF21, but that's because real curation isn't undertaken for money.