Your 10 PDCs have a combined PPV of 300. Where is the other 180 PPV coming from?
That is the question, isn't it (I have no other ships in the system that contribute to PPV)
And almost inevitably, now that I've posted, I think I know what is going on.
The system has a total of 10 PDCs, providing 300 PPV. However, after taking a few measurements of the rate of unrest increase at various populations and extrapolating backwards, it seems that the rate of unrest increase would hit zero at very close to 480 million population.
So it seems that the 'Requested Protection Level' (of 375 (actually 377 now)) is right, and that my calculation that I have 300 PPV is right. And the 'Actual Protection Level' is
not in PPV despite appearances, but in million population. So I actually have 300 PPV which keeps 480 million population happy, and everything then seems to be consistent with that view.