When you select matrix options for a parent in the NetSuite user interface, child matrix items are created automatically. The CSV import process is different. Each parent matrix item and each child matrix item must be added or updated individually, and the CSV file should include a separate line for each parent matrix item and child matrix item. Otherwise, the rules for creation of matrix items in the NetSuite user interface generally also apply to matrix items imports.
Each child matrix item can have separate pricing data.
A limit of 2000 child matrix items are permitted for each parent matrix item.
You can use the Import Assistant to add child matrix items to existing parent matrix items. Use the Subitem of field to store the value of the parent matrix item for each child
You cannot use the Import Assistant to delete matrix options.
In the user interface, child matrix items inherit Units Type field values from parent matrix items. However, items imports set Units Type field values separately on parent and child matrix items. You should map this field for both parent and child items and include values for both in CSV import files. Also note that Stock Units, Purchase Units, and Sale Units values are dependent on Units Type values.
When you are using a CSV import for populating the facet field values, ensure that the facet field values are the same for the child matrix items. If the facet field values are not the same or they are missing for the child matrix items, the facet filter might not work as expected. This issue is observed only when you use non-matrix options as facet fields.