It's just dependent on who see's the post and decides to vote on it. There's nothing magical that chainBB does different than steemit, besides organizing the content differently. chainBB is designed to highlight active conversations and discussions, which will likely have a better chance at getting votes from the users reading.
I don't think there will ever be any consistency in the rewards you earn as someone posting, since it depends on the other users who read and vote :)
OK. lol. Thanks for clarifying.