(2)The deduction under this section shall be equal to the whole of such income referred to in sub-section (1), or an amount of three lakh rupees, whichever is less:Provided that where the income by way of such royalty or the copyright fee, is not a lump sum consideration in lieu of all rights of the assessee in the book, so much of the income, before allowing expenses attributable to such income, as is in excess of fifteen per cent. of the value of such books sold during the previous year shall be ignored:Provided further that in respect of any income earned from any source outside India, so much of the income shall be taken into account for the purpose of this section as is brought into India by, or on behalf of, the assessee in convertible foreign exchange within a period of six months from the end of the previous year in which such income is earned or within such further period as the competent authority may allow in this behalf.
