How UOM_CODE field on PO interface mapping works in WMS?

Summary:Please help us understand does this mean for UOM conversion to work for a custom UOM. The UOM class in Source and WMS system should be same. Does the system not consider the UOM conversion factor setup maintained in WMS.

Content (required): "UOM Codes shared by host/ ERP systems can be different value than the corresponding item facility/ item primary UOM in WMS. Interface will appropriately convert the quantity to item facility/ item primary UOM as long as valid conversions are defined & UOM class of shared UOM code is same as underlying item's UOM class. Blank values in the field will correlate to the Item's Primary UOM. UOM code column will be recommended to be used for sharing UOM code."