VC Required : Determines whether orders from this supplier will default as requiring vendor control. A value of Y means that all orders from this supplier will require vendor control. An N in this field means that vendor control will not be required.
VC PCT : Indicates the percentage of items per receipt that will be marked for vendor checking.
VC FREQ : Indicates the frequency in which items per receipt will be marked for vendor checking.
The second and third attributes are optional. Hope this helps. Thanks.