Similar wording across two legal texts does not by itself make every condition portable between them. The operative cause, the prescribed action, and its qualifications must be examined separately.
Accidental killing explicitly specifies a believing slave. A different expiation may simply mention a slave. The Hanafi response preserves the latter text’s unrestricted wording unless a legally adequate independent proof restricts it; the competing approach gives greater weight to the shared character of the expiations.