LOCAL oil firms cut gasoline prices but raised the cost of diesel and kerosene at the pump, continuing the price trend set last week.  Shell and Seaoil implemented a rollback for gasoline of 25 centavos per liter and a price hike for diesel of 30 centavos per liter and kerosene of 15 centavos per liter from 6 a.m. today (Tuesday).  Phoenix Petroleum and Eastern Petroleum announced similar price changes for gasoline and diesel from 6 a.m. Tuesday.  Beating them all, Flying V implemented its rollback by the same rates at 12:01 a.m. Tuesday.  Read more here.