DistributionWeight is only needed of there are more factories of this type (i.e. two refineries, end consumer). In that case the next factory will be choosen from a list and each is weighted by these factors.
Range: give the range the production falls into (if zero that it is always exactly the given production).
InputSuppliers[ good_nr ]=how many factories I will be connected. Giving a number will force at most that many factories. Was used in pak128 to make coal a scare resource. Usually set to zero (mean fít will be connected to as many as needed).
pax_level: like for many other buildings, the heigher the more factories are created. But I think this became obsolete with the new demand system.