S.S.I. exemption amendment creates a temporal exception to a prior proviso, altering application of the excise notification. Amendment to the S.S.I. exemption notification inserts a further proviso in paragraph 4 so that the preceding proviso shall not apply during a specified period from 22nd May, 1992 to 31st March, 1993, creating a temporal exception to the existing eligibility condition in the parent notification.