When you’ve upgraded “Fit Aircon” to install “Climate Control” it no longer takes supplies from “Make Aircon”. While this makes sense in a way, it would be good to be able to upgrade “Make Aircon” to “Make Climate Control” or have “Fit Aircon” accept supplies from “Make Aircon” regardless of upgrades.
Yup I agree. I just need to write code that allows upgrades to do this and then I think it would be a worthy improvement.