"Optimal" stats for Poker Table Ratings Premuim subscribers

I recently payed for a 200 player search subscription ($9 btw) at Poker Table Ratings. I haven't used one since thay started offering Premium info for players -- which basically includes a lot more detailed stats. Kinda cool.

But I'm wondering how they determine what they call "Optimal" stats. For those w/ a subscription, you'll notice that there is a thumbs up / thumbs down next each stat that corresponds to what they claim is optimal. Hmmm. It says whether that players stat is higher/lower/same as "the top winners." This of course is seems highly subjective, but they must have their own weird formula for this. Or do they perhaps sample the players w/ the highest BB/100 for that game type & that limit and use it as their "optimal" number? Anyone have an idea or guess? Really curious.