Cebu Pacific Air on line booking

Cebu Pacific's on line booking at www.cebupacificair.com allows a passenger to purchase ticket much earlier than the flight date at cheaper prices.
Cebu Pacific's advice is to book as early as possible, as the rates are cheaper, compared to buying tickets on or shortly before the flight date.
The gimmick seems to be, the earlier you book, the cheaper the price.
But this is not correct at all times.
In my case, I booked a flight from Manila to Cebu many months before the scheduled trip.
I was happy because when I booked it, it was cheapest at P568 excluding the surcharges.
The total price for the one-way, Manila-Cebu ticket cost me P1,800.
However, just two months before the flight date, Cebu Pacific introduced a promo where the lowest price, excluding the surcharge was at P199.
Including the other charges, the total cost of the ticket for the same date was only at P1,197.
I could have saved P600 had I bought the ticket two months before the flight date.
Thus, even if I had booked and bought a ticket on-line many months earlier, it didn't necessarily mean I bought it at the cheapest price.