大方廣佛華嚴經隨疏演義鈔 69.63

69.63

疏「若總開三界五趣則具十」者，色身兼欲色二界，加無色為三界，集業煩惱為二，報身即五趣報，故為十也。

Regarding the Commentary's statement, "If one broadly unpacks the three realms and the five destinies, then ten are complete": the physical body encompasses both the desire and form realms; adding the formless realm makes three realms; the accumulation of karma and afflictions makes two; and the reward body is the retribution of the five destinies; therefore, there are ten.