I really doubt the documents that you have acquired at the Municipal Office; because the NSO is solely reliant on the Docs submitted to them by the LGUs.
@josephine bonifacio, there are ten (10) steps to be undertaken in the correction of an entry in a civil registry document
Contact a lawyer who will prepare the Petition for Correction of Entry.
Lawyers shall file the Petition in the Regional Trial Court. The fee for filing the Petition in the Regional Trial Court is Php 160.00.
The Petition will be raffled and assigned to a branch of the Regional Trial Court.
The assigned Regional Trial Court shall issue an Order for the publication of its Order in a newspaper of general circulation for three consecutive weeks. Fee for publication varies.
The Order contains the date of the first hearing.
During the first hearing, the lawyer will present compliance of the jurisdictional requirements like publication of the Order in a newspaper of general circulation.
After establishing compliance with jurisdictional requirements, the petitioner will be presented in Court to testify. The Court may assign the Clerk of Court to receive evidence.
During the hearing, it is possible that an oppositor may appear contesting the Petition. If no oppositor appears, the Clerk of Court will receive the petitioner's evidence.
After presentation of evidence, the Court will rule on the Petition.
If the decision is favorable, the Court will order the Office of Civil Registrar to correct the entry in the civil registry document (birth/marriage/death certificate of the petitioner).