The Regulations Governing Disbursement of Labor wage in Prisons and Detention Centers Article 5

The total labor wage as per working hours shall constitute 30% of the total labor wage.The allocation of the total labor wage as per working hours shall adopt the point system in which one labor point shall result from daily working hours less than four hours; two labor points from four hours to less than eight hours; and four labor points from eight hours to less than twelve hours.
中文原文 監獄及看守所作業勞作金給與辦法第5條
作業時間勞作金總額計算方式,按勞作金總額提百分之三十計算之。
前項之分配方式採點數制,以每日作業時間四小時以內為一點;超過四小時至八小時以內為二點;超過八小時至十二小時以內為四點。

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