四分律行事鈔資持記 2.1125

2.1125

所對三中。除儉者，律中儉開八事，不作餘食法，是其一數。言未足者，律云食已為他作不成（準《僧祇》開）。

In the three regarding the person faced: "Except during famine" refers to the Vinaya allowing eight matters during famine, of which not performing the leftover-food rite is one. Stating "not yet satiated" means that the Vinaya states that performing it for another after having eaten is invalid (allowed according to the Mahāsāṃghika-vinaya).