瑜伽論記 2.40

2.40

又解：身量以外，亦有麁妙等多差別，互有得失，壽量以外，更無餘能，故一向倍增也。

Another explanation: Beyond physical measurement, there are also many distinctions such as coarse and subtle, each having advantages and disadvantages; whereas beyond lifespan, there is no other capacity; therefore [lifespan] invariably doubles.