俱舍論記 23.131

23.131

「若爾上流至無第八生」者，難。若言一趣無第八生，上流遍生乃至有頂，亦應一趣無第八生。

Regarding the objection "If so, for one who flows upward [...] there would be no eighth birth": If you say that there is no eighth birth within a single realm of rebirth, then for one who flows upward and is reborn through all levels up to the peak of existence, there should also be no eighth birth within a single realm of rebirth.