I may be wrong as well but I thought TCI was a pickup and TCI tuned was a pickup that's been through the TCI process.
Example, Paul's Guitar is listed with TCI pickups. The Cu24 has 85/15 listed but now have the TCI treatment.
This.I may be wrong, but I believe they are the same thing. TCI stands for "Tuned Capacitance Inductance" so a tuned tuned capacitor inductance pickup would just be tuned twice! Just kidding, I believe that is just them putting the word tuned at the end to let people know they have been tuned using this method. Here is a PRS bit about them - https://prsguitars.com/news/story/p...w_models_new_finish_and_new_tci_tuned_pickups According to this, most =>2020 models now have TCI-Tuned pickups (same as TCI). I have seen plenty of these guitars listed without this information, but I do not believe there is a difference between TCI and TCI-Tuned.
The whole thing is something new and proprietary that PRS doesn't want to share with its competitors.
Paul has found a way to analyze and identify certain properties of a great sounding pickup, and then to tune the circuit (by picking the right values for pots, caps, resistors etc) to consistently reproduce them on a large scale.
So he has found some new measurable factor and figured out how to control it to get the response he wants consistently.
You won't find any special new parts or magical items if you take the pickup / circuits apart - I think it's just the combination of all the parts of the circuit he has chosen.
If I were him, I would not want to tell the world how I did that. But I'd want the world to know that I'd found something special.
Edited to add: I agree with what was said above, PRS have done a poor job of naming or explaining it consistently.