I don't understand it. I'm not even top percent, but "top 9%" (the unranked and unwashed bottom 99%) on "Stronger". It's only 2-dots difficulty.
"The Middle" or "All Star" would be better choices. I still golded those, and got a higher percentile on the leaderboards. And, they're 4-dots.
Those statistician gremlins need to be fired, then banished from this reality.