Quote Originally Posted by Assault and Flattery View Post
If you have 2 of the same item (like the Executive Coupe) it won't stack with itself.

Here's an example:

If the original building upgrade cost is 100%, -30% means upgrade cost is now 70%. If you subtract another 30% of the 70% you get 49%.
Now if you subtract another 20% of the 49% you get 39.2%. Their upgrading cost should now be at 60.8%, and we round that to 61%
Okay, now it's all clear to me. If this is the explanation for how bonuses stack with multiple units, then I really do understand why there are so many problems in the game. I was clear on the principle of how bonuses stack, since it's actually the same way that multiple discounts apply at a store or on any other purchase. But the conclusion here is exactly the opposite of what it should be: the actual upgrade cost given the calculations should be 39%, but the conclusion gets it a$$-backward and uses the "stacked" discount percentage as the cost percentage.

Yup, if you're doing exactly the opposite of what your own calculations tell you to do, then a lot of what happens in CC suddenly makes sense.