Is it permissible to transition to fasting before the prescribed time for the Hady obligation arrives?

Primary text

Transitioning to fasting before the time for the Hady obligation is permissible based on apparent inability (al-'ajz adh-dhaahir). The apparent state of the one who is unable (mu'sir) is the continuation of their inability and incapacity, similar to allowing expiation (kaffarah) via substitution before the obligation of the principal act is due.