Earlier this kind of expense was transferred to deferred revenue exp (advertisemnet suspense a/c or deferred advt exp ) because the expense was incurred in initial stage (current year) but there were enduring future economic benefits. Therefore as per matching concept people sought to write off the expense in no. of years
But however, Para 56 of AS-26 specifically mention to write such expenses in 1 go.
Reason being, no doubt there will be future economic benefits but THERE IS NO CONTROL over the benefit. You can't even qauntify as to how much benefit will you derive in each year. Therefore there is no basis on which such expense can be written off over the number of years and the main reason is ABSENCE OF CONTROL over the fututre economic benefit which is prerequisite to create an INTANGIBLE ASSET.
Therefore whole of the amount needs to be written of completely in the year in which expense was incurred.