Sri Lanka's statistics office says it is allocating changes in some prices over two months instead of taking the full increase in one period.
"This is only for administrative prices," the head of the price indices unit at the statistic office, D C A Gunewardena, said when questioned by reporters.
'Administrative' prices is usually a label attached to prices which the government interferes with. Such prices could include train fares, bus fares and fuel.
Gunewardena said the statistics office used the period of the final week of one month and three weeks of the following month to calculate its inflation number and there was a "practical difficulty" to be overcome.
If an 'administered price' is raised in the first week of the month, only three weeks worth of price increases are taken. The balance is carried forward, he said.
Gunewardena said the statistics office