I know that together these are overpowered, and also that having BOTH makes no sense. I have thought about this a lot, and thinking about other policy combos that make no sense (gay marriage + ban homosexuality) its clear that we need a system that makes pairs of policies incompatible.
So i’m implementing this now. Each policy will have a list of opposites. When you go to implement that policy, it will warn you that doing so will instantly cancel the opposites if they are currently active (no political capital cost for these cancellations in this case).
You can then go ahead or not.
I think this makes a LOT more sense than any attempt to fudge the existence of both taxes using clever algebra. Its clear and simple and decisive, and can be done relatively easily. Plus as I said, it allows for other pairings that make no sense to be fixed too.
Coding it now!