No reassessment after 4 years to disallow sums paid to NR if assessee had already disclosed all mate

IT/ILT : Where during original assessment proceeding, Assessing Officer had accepted assessee's explanation that payment of advertisement expenses to American company was not liable to deduction of tax at source and it was not case of Assessing Officer that assessee had failed to provide all material facts, he had no jurisdiction to reopen assessment after four years to disallow such expenses for non-deduction of tax at source