Therefore, Fukai-no-Joten/ Fukaijoten mentioned in the former part is the law that justifies the succession of the throne from the grandmother to the grandchild and their shared rule, while Fukai-no-Joten/ Fukaijoten mentioned in the latter part are noted as the law of the nation's governance, and is used in a context in which the empress wishes it's effect to continue.
よって、前段の不改常典は祖母から孫への譲位と共同統治を正当化する法であり、後段の不改常典は食国の法でその継続を願うという文脈である。