I see that there are two csv imports for inventory levels per location. One is here Transactions->Inventory->Adjust inventory worksheet->Import and another one is here Setup->Import/Export->CSV->Transactions-Inventory adjustment. The mapping is slightly different, so the question is which one to use?

Adjust Inventory is when you want to adjust the inventory by certain number. Adjust inventory worksheet is when you want to replace the number. I.e. If you counted 15 but you have 20 in NetSuite by Inventory worksheet you will type in 15 and by Adjust inventory you will reduce quantity by 5

You most likely want nothing to do with an inventory worksheet...try to avoid if possible

Yeah I like Adjust Inventory too, but i was just explaining the difference since he asked