It's actually 57.5%. The concept for this team was to draft a roster full of 10 to 11% usage players with high FG%, many boards, and full minutes (e.g. 19680 min). The team averages 60 boards per game in real life. I wanted to create a super rebounding dominate team again like my Roy Roger's Chicken teams of the years past.
I don't recall the possession penalty was supposed to affect TOs. It was for FG%. And for individual players. Dropping the shooting % if the player shoots above his normal amount (where the normal amount is adjusted, I assume, by pace -- slow-down, half-court, uptempo).
The theory behind my team concept was to keep the usage % low so as to spread out the possessions to all of the players in order to minimize the penalty.
So far I'm 1-0, scoring a whopping 100 points on 51% shooting and 22 TOs from a team with 1016 total TOs in real-life.
If you want to test the penalty, draft a high FG% player like the 67-68 Wilt. Surround him with low usage players so Wilt would take most of the shots. Watch his FG% drop like a rock from 59 to 40. He went from 1300 FG in real life to 2000 in the sim.
On a related note, those low usage players seem to make better defensive teams.