成唯識論述記 3.257

3.257

述曰：謂諸異生生無色界，預變無用，現無身故。生有頂天壽八萬劫，不妨欲界數度成壞，變之何用。

The Commentary states: This means that for ordinary beings born in the formless realm, transforming in advance is useless, because presently they have no physical body. If one is born in the highest heaven of the form realm, having a lifespan of eighty thousand kalpas, that does not prevent the desire realm from forming and disintegrating several times; what purpose would there be in transforming it?