俱舍論頌疏論本 14.58

14.58

釋曰：前兩句明成善惡表，下兩句明成無記表。表正作成中者，此表謂律不律及處中表也，正作此表業，恒成現在，名為成中。

The explanation says: The first two lines clarify the possession of wholesome and unwholesome manifestations, and the latter two lines clarify the possession of neutral manifestations. "While actively performing a manifestation, one possesses it in the present": this manifestation refers to manifestation of discipline, non-discipline, and intermediate manifestation. When one is actively performing this manifest karma, one constantly possesses it in the present; hence it is called "possesses it in the present".