To be honest I wants to know this too.so I resteem and up vote from two accounts this article!
I hope it will help answer on these questions.
Best votes-bot which I know and used is Minnow Booster.
the important thing is that votes don't even matter for visibility of the article.
but what you can expect is reputation points which you get when you get many votes. it is what you didn't mention.
I am afraid that your calculation are accurate:/
Personally my last rewards is smaller than I expected
RE: Upvote bots: Do they really work?