SELECT 
iv.Artigo
,iv.Stock, TotalNS = NS.Total, * 
FROM INV_ValoresActuaisStock iv
LEFT JOIN
(
    SELECT Total = COUNT(*), Artigo, Armazem, Localizacao, Lote
    FROM INV_NumerosSerie NS
    WHERE NS.Stock = 1
    GROUP BY Artigo, Armazem, Localizacao, Lote
) NS ON NS.Artigo = iv.Artigo and NS.Armazem = iv.Armazem and iv.Localizacao = NS.Localizacao AND  iv.Lote = NS.Lote
INNER JOIN Artigo a on a.Artigo = iv.Artigo and a.TratamentoSeries = 1
WHERE ISNULL(NS.Total,0)<> ISNULL(iv.Stock,0) and ISNULL(iv.Stock,0) <> 0
order by 1