On any appeal from a tax or other public accounts settlement of the fiscal officers of the Commonwealth, no facts shall be admitted in evidence that were not brought to the attention of said fiscal officers in the report filed, or in an application under oath for resettlement, prior to said appeal, and set forth in the specification of objections contained in the affidavit accompanying the appeal, unless the court shall be satisfied that the appellant was unable, by the exercise of reasonable diligence, to have laid such evidence before the said fiscal officers.
72 P.S. § 4144