Btw, I just did a test- with a whooping 3800 piety...
In one year, on very hard, I lost just ONE PIETY POINT. 12.9 - 11.9
I assume this means that badboy reduction is capped at one point (on very hard) in order to keep people with high piety from getting off too easy when it comes to badboy?
If that's the case then the maximum piety that's important to have on VH is at least 560-600 at any given time. Anything beyond that just earns points with the Pope.
Now then, just tested it on very easy! I lost almost exactly 5 badboy in one year on very easy!
So- 5, 4, 3, 2, 1 badboy loss limits for each difficulty level!