I was having some trouble visualizing the breakdown of curator vs. author payout, so I created some charts to help out!
So FAQ explains that the payout is determined by a linear relationship, then goes on to provide 5 examples to demonstrate what it meant. Without thinking too hard about it, it would seem that there were just five tiers or thresholds where the payout differed, but this is incorrect. Since the payout is perfectly linear, it differs with each passing minute between the author's post and the curator's upvote. This is shown on the line graph below:
The following pie charts illustrate the 5 examples that the FAQ page details.
As you see, it is far better off for the curator to wait until after the 30 minute mark to upvote if he/she is determined to maximize their payout.
I had trouble with the time factoring of it because it seemed that the curator should get more reward for upvoting before anyone else saw it, hence being a curator. But this is how the platform has implemented the system, so there you go. Use it as you wish!