Do you know what's missing?
I use a simple XL spreadsheet that includes production of the businesses owned by the town. The number of plants needed is calculated based upon maximum efficiency and 9+ units, so there may be a slight discrepancey to the actual demand.
You just enter the number of businesses you place in each town. The demand for raw materials is automatically updated.
The spreadsheet in MS XL format is
here
Other differences may come from the fact that town-owned businesses are not fully staffed; an important fact at the beginning of the game.