(2)For the purpose of clause (a) of sub-section (1), the gross income of [an intermediary] [Substituted by Act 20 of 1954.] from royalties shall be the average annual income on account of royalties, calculated on the basis of the annual returns filed by the [intermediary] [Substituted by Act 20 of 1954.] for the assessment of cess or income-tax during the period of twelve agricultural years preceding the agricultural year in which the date of vesting falls, or any shorter period for which such returns have been filed, and the net income from royalties shall be computed by deducting from the gross income so determined the average of the income-tax [and cess] [Inserted by Act 16 of 1959.] paid thereon during the said period and the cost of collection at such rates as may be prescribed:Provided that any sum shown in either of the said annual returns as having been received by the [intermediary] [Substituted by Act 20 of 1954.] by way of salami or premium shall not be taken into account calculating the gross income from royalties.
