If you want to use ExtendInsights to update the price of an item(s) on a NetSuite record, the ExtendInsights cell operation (picklist) will not display a Custom value in the drop-down list due to a NetSuite WebServices limitation. To customize a price level do the following:

Step 1: In the Item List: Price column, enter [[-1]] which is the internalID for Custom Price.

Step 2: Enter the Custom Rate in the Item List: Rate column.

Step 3: Click Upload and then Upload Records on the ExtendInsights toolbar. ExtendInsights will then create or update that record with the Custom Price level.