When the interest on refund prescribed in Article 58, paragraph (1) (Interest on Refunds) of the Act on General Rules for National Taxes is calculated for a refund under paragraph (1), the period referred to in that paragraph which serves as the basis for that calculation is the period from July 1, 1966 to the date on which the decision to pay out that refund is made or the date on which an Appropriation of that refund is made (or, if there is a date before that date on which the refund became suitable for Appropriation, that date).