Then I don't understand anything. I tought the aotobuys we're perfect, so if I buy manually is cheaper? I didn't see that anywhere.
And the autosell is only 100% with and engineer right? I can't spare and engineer for that, I only have 3, I need one to buy coal, one to buy oil and one for research. So I need to sell manually.
No, autobuys are perfect, they have no running costs - but you as a player can generally buy a lot of something when the price is low and live with that, and that is more effective cost-wise.
If you have 3 engineers, you can automate autosell and have everything running well, if you decide to drop coal or oil. Save the one that gives the most profits; the rise of selling efficiency to 100% should be well worth the drop.
Well, having to be smart with your engineer placement was intended a bit, so you would never actually have enough to fill all those 10 slots (but, to be honest, most of them are not needed - you only need the plant that is the best for you at this moment, for instance).
The engineer cost scaling is 100 (the cost of each next engineer is 100 times higher), but it is divided by the population squared, so the population has a big effect on the cost. It was probably a bad design decision, since it is hard to recover if you lose energy output.
