SINGAPORE  - Pakistan State Oil has extended the closing and validity dates of a term tender to buy fuel oil for a second time, a tender document showed on Tuesday.PSO, which typically seeks supply through the spot market, in July issued the rare tender to import 2 million tonnes of high sulphur fuel oil (HSFO) over a 12-month period, and the tender was to close in August.The company initially deferred the closing and validity dates to Oct. 30 and Nov. 30, respectively, to make changes to the terms of the tender.“Certain terms like the credit period of six months is too long, and I think that deterred people from participating,” a trader said. The reasons for the second deferment are not known.The tender now is due to close on Nov. 12, with offers to remain valid until Dec. 31, the document showed.