The Demand field in each Monthly and Weekly record is used to record Item Demand. Demand is the number of units that would have been sold from the selected location based on the invoice zipcode being shipped to, and the preferred shipping location you have identified for that zipcode.
In other words, the Demand field stores the number of units of this item that would have been shipped from this location if the item was available in this location (based on the preferred shipping location tied to each invoice zipcode).
For example, if you invoice a customer from the CA location but the customer zip code is in NY and the preferred shipping location for the invoice zip code is defined and it is set to NY, the sale of the item would be recorded in CA but the demand for the item would be recorded in NY.
In this case, the sale is made from CA, the Units field, and Total units field for the CA location is updated, and the Demand field for the NY location is updated.
The Demand logic is the same for warehouse shipments and vendor shipments.
Preferred Shipping Location.
If you load one of your valid warehouse locations into the Location field in the records in the Zipcode file, you are defining the preferred shipping location for shipments to that zipcode. For example. If you enter a warehouse location for your CA or california warehouse into the zip code records for the states of california, arizona, new mexico, nevada and oregon, you are telling the system that the preferred warehouse location for shipments to these states is the CA warehouse. The location field in the zipcode records is optional, but if loaded, it is used to calculate the demand for the item.