Quantity field elements in the RESB table

Hello!

Can you please let me know how the field, NOMNG (Required Quantity), differes from the following quantity fields in the RESB table and how the NOMNG field is used and from where it is populated? I'm looking at component requirements for subcontract purchase orders. I am using ECC 6.0, EhP4.

1. BDMNG - Requirement Quantity - I understand this is the required quantity in the base unit of measure.
2. ERFMG - Quantity in Unit of Entry - I understand this is the quantity in the Unit of Entry UOM that comes from the BOM. We have a few BOMs where the quantity is in a UOM that is different than the base unit of measure.

NOMNG - Required Quantity - Not sure what the purpose of this field is.

Thanks very much in advance for any guidance.

Chris