Yes, economy of scale is a thing. :)

Also some cities has more expensive materials than others.

Sorry, I missed this thread.

This confused me:

So i have a little problem where my material costs are about 64 mil but there are another 76 mil of material costs across all factories (line and labour costs are only 13 mil)

I assume you mean you have a material costs of $64 Million, Total Factory Costs of $76 Million and line + labor around $13 Million.

Material costs are the unit costs of the vehicles you're making. So if your cars' unit costs are $10,000 and You're making 6,400 vehicles a turn, that will account for your $64,000,000 Material Costs.

Your Material Costs + Your Line Costs + Labor Costs = Total Factory Costs.

Using your numbers, assuming you're rounding, 64 Million + 13 Million = 76 Million.

Excuse me for my clunky english. And yes, you were right, the factory cost were fine I just somehow missed how huge my taxes and marketing costs were while looking out for some hidden material costs... Sorry, and thank you!