I have not tried, but i've seen some calculations. How those upvote-bots work is that there is a round when everyone can put their money in. The voting-power % that is used is calculated from your contribution to that bidding round compared to others. There has been increased demand for these bots which means that more people are participating into bidding rounds causing % upvote from that bot to be too small for profit in some cases. Check out https://steembottracker.com/
also check out @grumpycat for more info about what he is doing.