No worries I was absolutely confused when I tried to understand it as well. I believe that there is an algorithm which determines curator rewards. The entire piece of the 25% pie is split based on the percentages in which the curator's upvote lies in each time bracket. So that means if the curator reward totals up to $10 then that piece of the pie is split amongst each individual who upvoted it to spread awareness. The percentages given by Steemit are just an overall guideline of where you would lie for curation rewards. But because there are so many factors involved such as number of upvotes followed, curator steem power, and the time in which you vote; there is really no way to figure out the algorithm.

I guess to answer the first question yes you would get all 10% of the curator rewards if no one comes after you. But overall, it is a mathematical equation that determines exact rewards. These time brackets are just a guideline so that people don't abuse the system and upvote each time a post comes out hoping to get 100% of the curation reward.