No reassessment to curtail sec. 10B relief if AO couldn't prove failure of assessee to begin product

IT : Where assessee, an export oriented undertaking, claimed that it purchased raw material in form of ROM and finished goods of various grades being manufactured therefrom had been exported and Assessing Officer held that assessee did not purchase ROM and accordingly curtailed its claim for deduction under section 10B, in absence of any evidence to show that what assessee purchased was not ROM, conclusion drawn by Assessing Officer was unsustainable