Cost type is required while we define any new organization.

Some cost types which are already defined are Average and Frozen.
Steps to Define.
Choose inventory responsibility and navigate to form.
Setup -> Costs -> Cost Types
On Cost Type Window

Default cost type is basically used for items where any specific type is not defined.
Date to inactivate cost is used to inactive your cost at specific date except for average and frozen cost type because frozen and average cost cannot by inactivate.
If multi org is checked then this type is available for all organization but not its costs.
If unchecked then this type is only available for organization which created it.
If allow update is checked then this cost type can be updated by available average cost update processes.

If for this type you want component yield effect in rollup then check this box.

Once Cost Type is defined let’s Move forward to Defining and configuring Inventory Organization

This post will cover API ego_item_pub.assign_item_to_org used to assign item to an organization.
Step by step demonstration of code.
Please download attached file to use as sample code. This sample code assign single item at a time to single organization you can modify it for multiple items or multiple organizations at a time.
This API assigns a specific item to any inventory organization. The item to be assigned must already assigned to parent organization before running this API.

Input parameters.
P_param1                   pass inventory item id.
P_organization_id      organization id to which you want to assign item
P_organization_code organization code of specific organization


Variables need to be assign values by you.
l_user_id                     your used id
l_resp_id                     your responsibility id
l_application_id          application id

Get this information from fnd_responsibility table.

Running attached code I recommend to run it initially for some items and verify that these items are assigned to specific organizations.

Download.