The second one, where it mentions the 180 in the post along with the formula(I've edited my original post). I definitely can confirm 10 profs over does not result 50% effect. I made direct observations from my province, and KD mates at/around 30 profs over the cap, and the categories come out at about 70% of what they would be if those professors were giving full effects.
@Wilmington I did not try to use the other in-game examples of diminishing gains, like you suggests, so its entirely possible.
I'm just using simple excel trendline to make the curve... I would imagine its a cubic function... around the 180 point it has more or less leveled out, I expect with info that went beyond there we would see the rate of diminish pick up again.
@yootohpeega I am not sure what you mean... every 2X = 1 Professor