I tried the samples and the function works correctly in the Select query.
SELECT JuntaMesAnoValor.IdAdv_DataSusp, ConcatRelated("MesAnoValor","JuntaMesAnoValor","IdAdv_DataSusp = '" & [IdAdv_DataSusp] & "'","QuotasSolicitadas") AS Mensal, Len([Mensal]) AS Tamanho
FROM JuntaMesAnoValor;
But...