Which event is better to use to change quantity after import?

Question

1C-Bitrix

I hung up the change in the number of goods on the OnSuccessCatalogImport1C event, but as I understand it, it works after 1 package of changes (3k products, and 300 packages each), it turns out that after 10 xml packages, I have an inadequate number of products. How can this be fixed?

AddEventHandler('catalog', 'OnSuccessCatalogImport1C', 'quantityCatalogImportStep');

function quantityCatalogImportStep() 
{
  $addProps = CIBlockElement::GetList (
  Array("QUANTITY" => "ASC"),
  Array("IBLOCK_ID" => 18),
    false,
    false,
      Array(
      'ID', 'QUANTITY', 'NAME', 'PROPERTY_MIN_UPAKOVKA'
      )
);
while($ar_fields = $addProps->GetNext())
{

   $kolvo = $ar_fields['QUANTITY'];
   $min_upakovka = $ar_fields['PROPERTY_MIN_UPAKOVKA_VALUE'];
   $new_kolvo = (int)($kolvo / $min_upakovka);
      if ($ar_fields['QUANTITY'] > 0 && $ar_fields['PROPERTY_MIN_UPAKOVKA_VALUE'] > 0) {
  echo 'Товару с ID-' . $ar_fields['ID'] .' установлены параметры';
  echo 'Новое количество:' . $new_kolvo.'
';

  
  Cmodule::IncludeModule('catalog');
  $PRODUCT_ID = $ar_fields['ID'];
  $arFields = array(
    'QUANTITY' => $new_kolvo
  );
  CCatalogProduct::Update($PRODUCT_ID, $arFields);
    }
}
}