Philippines has some odd laws about issuing tickets. I don't know if it's protectionism or that they require (though don't always enforce) that all foreigners arriving have a ticket out.

Until fairly recently foreign airlines serving MNL could not sell tickets ex-MNL by web. This has changed so maybe the award procedure has changed, too.

Orbitz still will not search flights ex-MNL. Peculiar & really a lot of hassle.