We are saying similar things. Average prices in the WESM are...

We are saying similar things.  Average prices in the WESM are quite low; they are high enough to justify merchant sales from an OCGT well less than 20% of the hours in the year these days.  When Meralco buys from WESM, it is mostly at peak times and mostly at times when e.g. the Malampaya plants are producing less (maybe because of field maintenace) so the average of Meralco's purchases are at prices higher than the WESM average. If an OCGT is dispatched on the economics, 1,000 hours or less would be my guess, and this is what is happening to the OCGT plant of FirstGen called Avion.
See this article for example: http://www.philstar.com/business/2017/03/21/1682983/power-spot-market-prices-drop-6-yr-low-jan
Couple of other things.  Efficiency should be better than 33% though hard to accurately predict -- these are older (though never used) turbines, built nearly 10 years ago at this point I believe; I calculated my range on 38% efficiency.  Japan has two LNG reference prices, contract prices that average around 15% Brent, and spot prices that much of the year have been significantly below that level but now, in the midst of pre-winter buying, may be a bit higher.  It is hard to assume that a buyer in the Philippines will get a better deal than a Japanese buyer.  That will logically be true for some supplies when the Philippines is closer to the supplier (ie not for Sakhalin LNG), but the logic holds only if the buyers are of equal credit strength.  If not you might see some risk premiums attached.  Also remember that the price  of gas into the trubine also has to include at a minimum the operating costs of the LNG  terminal, including regas.  If you try and also recover fixed terminal costs, you would be adding perhaps $2 per mmBtu to the LNG cost.
$85 coal -- at 40% efficiency, works out to 4 cents per KWh, or 2 pesos, and this is why average WESM prices are around that level because variable coal costs are setting marginal prices for much of the day.  And the only reason that coal prices are at that level is because of policy intervention by the Chinese govt.  see https://www.bloomberg.com/news/arti...der-resuming-coal-output-curbs-for-six-months