That other location is, in fact, the very treatise now before us.
Ibn Rashīq (may Allah have mercy on him) referred to this rule under the title, “A Rule on tasbīḥ, taḥmīd, and tahlīl” (1). The eminent scholar Ibn ʿAbd al-Hādī (may Allah have mercy on him) mentioned it under the same title (2). This wording is very close to the title found on the manuscript itself: “A Fine Rule on the Enduring Righteous Deeds, explaining the pairing of tahlīl with takbīr and of tasbīḥ with taḥmīd,” which I have adopted here because it best reflects the content.
Anyone who consults Shaykh al-Islām’s discussion of this rule in other parts of his works (3) will see, beyond any doubt, that it matches precisely what appears in the present treatise.

Description of the manuscript:
I have relied on a single copy preserved within a composite volume that gathers several of Shaykh al-Islām’s treatises. The volume is housed in the “Khizānat Raʾīs al-Kuttāb” annex of the Süleymaniye Library in Turkey, under shelf-mark 1153.