Lopez can actually start to reconcile his alleged overprice by getting his figures right.
WHERE ARE THE FA-50 MULTIROLE FIGHTER JETS OF THE PHILIPPINE AIR FORCE?
The Benigno C. Aquino III administration as recommended by then Defense Secretary Voltaire Gazmin and approved by Executive Secretary Paquito Ochoa acquired 12 units of Korean Aerospace Industries ( KAI ) FA-50 jet aircrafts costing US$ 464-Million as among the major acquisitions of the P 170-Billion AFP Modernization Program.
The official DND value was actually US$421,638,000.00. A copy of the DND's Notice of Award to KAI appears below.
It's worth noting that later in his thesis, Lopez assumed that the per-aircraft value of the FA-50 is based on his inflated figure above . . . merely divided by the number of aircraft. Completely ignoring the cost of spares and training of PAF pilots that were included in the Integrated Logistics Package of the FA-50 that is mandated by DND regulations.

Many millions more were spent for munitions including missiles and bombs to hit air and land targets.
Ammunition and ordnance were not actually included in the FA-50 purchase. Weapons were to be purchased separately. See
here.
The overpriced, unproven and limited production jet aircrafts were advertised as Multirole Fighters ( MRF ) for air defense, ground attack and reconnaissance using air-to-air, air-to-ground missiles and precision guided bombs. The original T-50 aircraft was designed as an advanced jet trainer following the LIFT concept.
The KAI FA-50 light fighter aircraft was advertised as capable of attacking ground targets with Maverick air-to-ground missile, JDAM and other precision bombs, guided by Israeli-made Elta EL/M-2032 radar fire control system.
The features, performance envelope and combat capabilities were cited to justify the high price tag of about US$ 38.66-Million per unit as contracted by the Department of National Defense for the Philippine Air Force. However, my research indicate an overprice of around US$ 8.66-Million per unit, when compared to the acquisition price of the same KAI FA-50 model acquired by the Republic of South Korea Air Force at US$ 30-Million per unit, with the Indonesian Air Force acquisition of the KAI TA-50 model optimized for attack role at US$ 25-Million per unit with provision for technology transfer.
Lopez cited no references for his figures.
Therefore it is not possible to ascertain the timeline for his valuation. The T-50 family of aircraft is a joint venture between Lockheed Martin and Korean Aerospace Industries that first flew in
2002. Since then, a number of version of the aircraft have been produced, culminating in the FA-50 received its Aircraft Worthiness Certificate in
2012 and entered thereafter.
To validate Lopez's assertions, he must clarify when in the aircraft type's operating history were these figures taken. Otherwise,
foreign exchange fluctuations -- not to mention inflation considerations -- cannot be factored into these figures. Consequently, it would be impossible to conduct a proper inquiry into his allegations of "overpricing". Note the volatility of the South Korean Won over the course of the T-50 family's life.

It is also unclear which version of the
T-50 family of aircraft Lopez was comparing his valuations against.
The South Korean air force uses the following versions of the T-50 family:
T-50 - Lead-In Fighter Trainer
T-50B - High performance aerobatic aircraft
TA-50 - LIFT / Light Attack (discontinued)
FA-50 - Light Attack
Each aircraft have their own specifications . . . and therefore have their own -- still-undisclosed -- acquisition costs. Assuming Lopez really had basis for his values, to which aircraft were they for?
As for Lopez's comparison with Indonesia. Unlike the PAF's FA-50 which have both a training and combat function, the Indonesian T-50i are primarly trainers, and were reportedly delivered in 2014
WITHOUT intercept radars. It would arguably be safe to assume that this will affect any attempt at an apples-to-apples comparison with the fully equipped Philippine aircraft.

After PRRD criticized the Korean-made aircrafts as useless and good only for fly-bys, sources from the PAF leaked serious technical issues of incompatibility/integration between the FA-50's radar fire control system with the U.S. Sidewinder air-to-air missiles, and perhaps with the Maverick ground attack missiles, JDAM and precision guided bombs it was suppose to carry for the required combat missions. After 10 days of intense fighting in Marawi, the PAF could have deployed these MRFs for precision ground attack role. So far we have witnessed only helicopters and propeller-driven SF260, OV-10 Bronco light attack aircrafts doing ground attack, using unguided 70mm air-to-ground rockets, machine gun pods for strafing and conventionally dropped bombs. No precision ground attacks vs. the Maute-ASG-ISIS terrorists using radar guided AGMs and JDAMs by the KAI FA-50 light combat aircraft fleet costing US$ 464-Million ! Perhaps this is the reason why DND Sec. Delfin Lorenzana went public to reveal the shortcomings faced by our soldiers fighting on the ground and pilots providing air support.
The PAF has officially acknowledged that FA-50s were used in combat for the first time in January 2017 against the Maute group in
Butig, Lanao del Sur.
Chiara Zambrano also tweeted the following photo of an FA-50 over Marawi.
