Ajuda p/o campo (PNH1VOFLG) 

This field is used to define whether the return is likely to generate a credit memo.
When the returned goods are already invoiced, this field is initialized to 'Yes' (in the case of a return for an invoiced receipt). The credit memo will then be constructed from the return.
When the returned goods are not yet invoiced, this field is initialized by default to 'No'. Therefore, in principal, no supplier credit memo is expected, but an invoice taking into account the returned quantities or even replacement parts shipped by the supplier.
The purchase invoice lines, pre-loaded from the receipts that have been the object of a return, will be decreased up to the level of the returned elements.
It is however possible to force this field to 'Yes'. In this case, the purchase invoice lines must be pre-loaded from the order (in order for all the ordered quantities to be submitted). It is then possible to create a credit memo from the return lines.