I hope this post answers most of your questions.
You are in the flag side of things for this given day, not the downvote, and as most bigger fish seem to flag against posts strongly positive RSHARE post status, you often don't need all that much SP to have a single 100% flag against a zero RSHARE post end you up in the top 25.
I'm open to suggestions for making things better. Currently considering switching the flag section to a top ten instead because of this. Not sure yet though.