G.R. No. 182267 - Hadji-Sirad vs. Civil Service Commission

On March 15, 2004, petitioner Taisei Shimizu Joint Venture (TSJV) entered into a construction contract with the Department of Transportation (DOTr) for the New Iloilo Airport Project.
Upon project completion, several billing claims by TSJV remained unpaid, prompting TSJV to seek redress.

TSJV filed Request for Arbitration with the Construction Industry Arbitration Commission (CIAC) in 2014, asserting eight money claims totaling Php 2,316,687,603.03 (plus interest and VAT).
The CIAC’s Final Award (Dec. 11, 2014) granted Claims 1, 3, 4, 5, and 8 amounting to Php 223,401,870.83 plus 6% interest per annum.
On DOTr’s motion for correction, the CIAC Order (Feb. 20, 2015) reduced Claim 3, resulting in a final award of Php 216,073,986.89.
TSJV sought execution; the CIAC issued a writ of execution, but garnishment attempts failed as DOTr agencies deferred to COA approval.

TSJV petitioned the Commission on Audit (COA) for enforcement and payment of the arbitral award. DOTr, via OSG, admitted the award’s amount and finality.
By Decision No. 2016-395 (Dec. 21, 2016), COA approved only Claim 4 (Php 104,661,421.35) and disallowed Claims 1, 3, 5, and 8 for alleged non-compliance with RA 9184, PD 1594, EO 40, and the Rules of Court.
TSJV’s partial motion for reconsideration was denied by COA Resolution No. 2018-047 (Jan. 22, 2018), with COA reaffirming disallowance; COA Chairperson dissented, opining COA cannot modify final awards.

Does the COA have exclusive jurisdiction over money claims due from or owing to the government?
May the COA, in exercising its audit power, disturb final and executory decisions of courts or other adjudicative bodies?