The formula in the code takes into account the difference between the minute you upvote and 30 minutes. If your time is under the mark of 30 minutes, the differnce comes into play and the corresponding amount is given to author instead of you (the curator).
I'm not a coder so I won't go into more detail. But anytime before 30 minutes does have a negligible to significant effect on curation rewards.
By 100 % of curation reward, I mean the 25 % of a single voter's vote value. For example, if I upvote a post with $1,l after 30 minutes, I am likely to get $0.25 worth of SP as curation reward.
But, it is not as simple as that because so many factors come into play; especially the people who voted before you.
ok, 25% of the vote value is awarded to the curator if voted after 30th minute and before 30th minute a portion goes to the author (because of the linear increase from 21st minute to 30th minute).
Thanks for your time to answer the query. Appreciate it :)
Most welcome.