A client wants to use group average costing, please explain if change will be productive or retrospective and will I need to update the costing method on the item record?

AI generated answer (using internal Slack threads):

****** Disclaimer: This response was generated by an artificial intelligence assistant based on previous conversations from multiple Slack channels, and may contain inaccuracies or mistakes. ****** Changing the costing method from 'average' to 'group average' in NetSuite is not directly possible. You would need to inactivate the current item and create a new one with the desired costing method. This change is not retrospective, it will only affect future transactions. If you want to keep your average cost unaffected for any reason, you will need to create a new SKU. Historical average cost for any given past transaction is captured as COGS, so that would remain. If you bought something at a higher price, the point of Average Cost would be to let it fluctuate. If you need to correct the Average Costing for an item, you can do so via inventory adjustments. If you adjust it negatively it will come out at its current average cost, so in theory that should bring current value/cost to zero (if you take out the total inventory quantity at a location). But when you adjust it back in you can specify the new cost. It's recommended to do the move-out IA first and separately (and on a different posting date) than the move-back-in IA, to keep things clean. Please note that depending on your system settings, average cost on the item record is not necessarily updated immediately after saving transactions - check your inventory costing preferences page.