Comment 8 for bug 1637788

The checks in the mill for corn and blackroot are identical - the mill skips producing blackroot if there is corn available and the economy needs cornmeal and does not need blackroot flour. So, if there is no corn available, the mill will just continue producing blackroot flour, and vice versa. All the economy limit does is make sure that cornmeal gets more production cycles when enough corn is available.

I agree it's not intuitive that more than the limit get produced, but I can't think of a better design at the moment.