You're confusing what I said earlier. I said flights to and from the United States, provided there's no promo, usually earn Mabuhay Miles. It's usually PAL's high-yield routes (Australia, Canada, Japan, Korea and the United States) that show fare classes with mileage accrual at the onset, while lower-yielding Southeast Asia does not, unless you pay the premium.

Domestic flights are a different story altogether. Fare classes W and U are designed not to earn miles because these are meant to lure passengers away from Cebu Pacific and Zest. In many cases, a W or U fare on PAL tends to be cheaper than a similar flight on Cebu Pacific. In this case, it depends on the timing.

However, Mabuhay Miles accrual is a perk I'm willing to bet people are willing to pay for. The premium, at least domestically, isn't that much: for example, MNL-CEB on fare class W (P1328 for WPX, P1516 for WPR, exclusive of taxes) does not earn miles. However, fare class T on this route is as little as P500 more (the fare is between P1900 and P2000, though the exact figure escapes me, and this is also exclusive of taxes). I'm inclined to believe that mileage runners won't gripe over $10, especially since the $15 fare is already cheap to begin with.