To import new quantities we can use Adjust inventory worksheet import . I have updated the inventory quantity by importing the inventory worksheet.
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Transactions > Inventory > Adjust Inventory Worksheet > Import
By using the Inventory Worksheet, the entire quantity is replaced with the new quantity.
By using a single CSV file, we can create only single inventory worksheet.
Maximum 1000 lines can be created per CSV file
When you use the Adjust Inventory Worksheet with LIFO or FIFO costing, the cost of any item you adjust is averaged. NetSuite ignores LIFO or FIFO, and your costing history is lost. To preserve LIFO or FIFO, use Adjust Inventory for any inventory adjustments. If you use the average costing method, you can make any changes you want on this worksheet.