Field help (PNHUOM)

In the case of a return created from a receipt, the default return unit is the unit entered in the receipt.
In the case of a direct return, the suggested unit is the purchase unit of the supplier or the purchase unit if the Product-supplier record has not been defined. Click the Actions icon to change the suggested return unit.
The list of proposed units regroups the stock unit, the product packing units, the product purchase unit and the different units defined for the supplier.