When you use the factory builder you must enter a production value.
1) Is it the units/month value?
2) Is it possible to change it during the game?
3) Can you better explain me the relation between Units/month and Consumpion?
Thanks
Yes
No. By adding electric power from a power station you can increase production to twice as much, but that's the only thing that can be changed.
Not sure that I understand your question. In one month a consuming factory (at the end of the production line) will consume the indicated amount of units of the goods it consumes.