The due amounts, age categories and endpoints in camel zakat are drawn from transmitted zakat schedules. Written zakat instructions attributed to the Prophet ﷺ and reports of the Companions form the basis of legal reasoning in this area.
The thresholds 25, 36, 46 and 91 are therefore not generated by a simple percentage formula; they follow a fixed transmitted schedule. Comparison and reconciliation of individual reports is a separate hadith-study question.