俱舍論疏 17.80

17.80

論「五俱轉者至得二支等」，明五俱轉。此亦是期心唯受二支，善意識現前，故有五也。等者，等取善五識現在前得三支，惡、無記心現前得五支也。

The passage of the śāstra from "When five operate simultaneously" up to "one obtains two branches, etc." explains the simultaneous operation of five. This also refers to someone setting their mind to receive only two branches: when a wholesome mental consciousness is present, there are five. "Etc." includes receiving three branches when the wholesome five consciousnesses are currently present, and receiving five branches when an unwholesome or indeterminate mind is present.