Each rifle conversion cost them USD 1068 (Peso 60,000). The average cost of the barrel assembly unit in USA costs around USD 540 (Peso 30,337). Looks like the Philipinos got cheated.
A new M4 would have cost them USD 1400 per rifle. Correct me if I'm wrong.
NB: Conversion rate 1 USD = 56.18 Philipino Peso.