Customer Items
- Customer items can be defined at customer category level, customer level and customer ship to level.
- For a single customer item we can have two differnt inventory items in customer cross reference with rank 1, 2 etc
- The process of difining customer cross reference is
1. Define commodity code 
2. Define customer item and 
3. Enter the customer reference.Use  the Customer Items Summary and Customer Items Detail windows to define  and update customer items. You can toggle between these windows with the  Summary/Detail option in the Go option on the Toolbar. You can cross  reference customer items to your Oracle Inventory items to support  processing orders and shipments.
A customer item defined at the Customer level is recognized across  all address and address categories for that customer. If you ship an  item to multiple customer ship–to sites that have been grouped as an  address category, you can define the customer item for that address  category. You would define a customer item at the address level if you  ship the item to only one ship–to site for that customer.
Commodity Codes
Customer Item Commodity Codes are used to group customer items and can be entered during the definition of customer items.
Navigation : INV -> Setup ->Items -> Customer Item commodity code.
Customer Item1. Select one of the existing Customer Names (in the Details window, you can use either Customer Name or Customer Number,).
2. Select the Definition Level: Customer, Address Category, or Address.
A  customer item defined at the Customer level is recognized across all  address and address categories for that customer. If you ship an item to  multiple customer ship-to sites that have been grouped as an address  category, you can define the customer item for that address category.  You would define a customer item at the address level if you ship the  item to only one ship-to site for that customer.
For the Address Category definition level, enter the address category.
For the Customer Address definition level, enter the customer address. 
3. Enter the Customer Item number and description.
4. In the Commodity tabbed region, you can assign the customer item to a Commodity Code.
5.  In the Container tabbed region, you can enter the default master and  detail containers for this customer item as well as the minimum fill  percent for the container.
6. In the Model, Departure Planning tabbed  region, you can reference a customer item as a Model by entering the  inventory item number of an existing Model item (the BOM Item Type  attribute is set to Model).
You can also check Required to indicate  that items must be departure planned before they released and Before  Build to indicate that ATO items must be departure planned before they  are built.
7. In the Demand Tolerances, Active tabbed region, you can  enter positive and negative tolerance percentages and select or  deselect the Active check box.
Customer Item Cross References
Use the Customer Item  Cross References window to define and update cross references between  your inventory items and the customer item numbers defined in the  Customer Items Summary/Detail windows.
You can also navigate to this window by selecting the Cross Reference  button in the Customer Items Summary window. Inventory displays the  existing cross references for the customeritem on the current line in  the Customer Items Summary window, and you can add new cross references  by selecting a new row.
Enter the Rank as a positive  number. To permit alternate or substitute inventory items for a customer  item, you can define multiple cross references to inventory items for a  single customer item. In these cases, you must specify the Rank of the  cross reference. The highest rank is 1.

 
 
Customer item ABCD has the same rank for 3 different items. Which one is referenced when ranks are the same?