俱舍論記 13.156

13.156

「表色唯在至可言有表」者，釋第四句。三性表業皆通欲界、初靜慮中。若言有尋，不攝中定。為攝中間，故言有伺。

Regarding "Manifest form exists only in... can be said to have manifestation": this explains the fourth line. Manifest karma of the three natures extends across both the Desire Realm and the first dhyāna. If one were to say it 'has investigation' (vitarka), this would not include the intermediate dhyāna. In order to include the intermediate [dhyāna], it says 'has examination' (vicāra).