Conceptually this is really solid, but does anything else happen? Or is it just a math game where you keep your numbers in line. I beat a couple rounds but after a while it felt like I was just doing the exact same thing. I think this would be a really cool core to build off of. Like for example if you had power ups like: "Greed is good" - Gain an # multiplier for each zone that is over 15. Or "Ecofriendly" - Business cards produce 1 less heat if two zones are less than 10.
I think allowing you to choose and unlock things like that as you progress will add a little complexity and strategy to the game rather than it being a purely mathematical exercise.