Enforcement Rules of Consumer Protection Act Article 22

“The amount of each installment” as referred in Subparagraph 2, Paragraph 2, Article 21 of the Act shall mean the installment payments with interest charges.The interest rate set forth in an installment contract shall specify the method of calculation thereof and the amount of interest calculated by using the rate.Other incidental charges shall be specified clearly in the installment contract and not be included into the installment payment for interest calculation purposes. The same provision shall be applied if traders agree to postpone the payment or let the consumer pay in installments.
中文原文 消費者保護法施行細則第22條
本法第二十一條第二項第二款所稱各期價款,指含利息之各期價款。
分期付款買賣契約書所載利率,應載明其計算方法及依此計算方法而得之利息數額。
分期付款買賣之附加費用,應明確記載,且不得併入各期價款計算利息;其經企業經營者同意延期清償或分期給付者,亦同。

English translation for reference only; the Chinese text prevails. Not legal advice.