If an individual who, in the calculation of business income for 1998, accounted for all instalment sales or similar transactions of Inventory or services prescribed in Article 65, paragraph (1) of the former Income Tax Act made in that year (hereinafter referred to as "instalment sales or similar transactions" in this paragraph) under the instalment basis method specified by Cabinet Order prescribed in paragraph (1) of that Article (hereinafter referred to as the "instalment basis method" in this paragraph) makes instalment sales or similar transactions of Inventory or services in any year from 1999 through 2003, then, in the calculation of business income for the year in which the individual made those instalment sales or similar transactions of Inventory or services (excluding those falling under deferred payment sales or similar transactions prescribed in Article 65, paragraph (2) of the new Income Tax Act; hereinafter referred to as an "instalment sale under the transitional rules" in this Article) and for each subsequent year, the amounts obtained by adding, to each of the amount of revenue and the amount of expenses that would be included in the gross revenue or necessary expenses for each of those years if the amount of revenue and the amount of expenses from that instalment sale under the transitional rules were accounted for under the instalment basis method, the amount specified in whichever of the following items sets forth the year in which the instalment sale under the transitional rules was made (or, if that amount exceeds the amount remaining after deducting, from the amount of revenue or the amount of expenses from the instalment sale under the transitional rules, an amount equivalent to the amounts already included in gross revenue or necessary expenses pursuant to the provisions of this paragraph for that instalment sale under the transitional rules up to the previous year, the amount remaining after that deduction) are included in gross revenue and necessary expenses, respectively: