My Aeroforce gauge can measure something called TCC Slip and Duty. What exactly do these values mean and what is a healthy range for them to be in?

 

Tcc slip is the amount of slip the torque converter has. When I was on the Dyno mine was slipping like 300 rpm which is terrible and probably hurt me an easy 40-50whp. Generally when tcc slip gets really high your torque converter is on it's way out the door, you can bump up line pressures in the tune to help but that's only a bandaid

 

So when do you want it to be as little as possible? All the time? When driving? WOT? I noticed I have a lot when idling in park but my understanding is thats normal because the clutch isn't engaged, but that could be completely wrong, I know very little about transmissions