VEIAV table gets only filled with MEIS transaction, uodates are only manually with VEFU transaction.
if a record has a billing date, then the invoice was already processed in MIRO.
if it does not have a billing date, then the invoice has not yet been processed, still the movement is due for the report if the movement happened in the month prior to the reporting month and was not reported last month. the value is then assumed based on the PO price