In fact, Mahākassapa Thera of Mahā-Parakkamabāhu-Katikāvata fame may have also composed a Subcommentary to the Abhidhammatthasaṅgaha.
“The reign of King Parākramabāhu the Great ushered in another great epoch of literary activity. Three great scholarly monks flourished in his reign, namely, Mahā Kassapa of Dimbulāgala Vihāra, Moggallāna Thera and Sāriputta Thera. Mahā Kassapa was the author of a Sinhalese paraphrase (sannē) to the Samantapāsādikā, which is now lost. He is also reputed to have written a sub-commentary to the Abhidhammatthasaṅgaha. It is probable that he was also the author of several other works such as the Mohavicchedanī, which is a treatise on the Abhidhamma, and Vimativinodanī, which is a commentary on the Vinaya. Moggallāna, a contemporary of Mahā Kassapa, was the author of the Pali grammar, Moggallāna-vyākaraṇa. He is also credited with the authorship of the Abhidhānappadīpikā, which is the only ancient Pali dictionary in Sri Lanka…”"…
"…It should be mentioned here that the ṭīkās named above formed one of the major groups of Pali literature compiled during this period. As described in the Saddhammasaṅgaha, a Pali work of the 14th century, Mahā Kassapa and a large congregation of monks who assembled at the Jetavana Vihāra at Polonnaruwa decided to compose exegetical commentaries since the existing sub-commentaries on the old Aṭṭhakathās were unintelligible. Acting on this decision they compiled ṭīkās, namely, the Sāratthadīpanī on the Vinaya Piṭaka, the Sāratthamañjūsā in four parts on the first four Nikāyas of the Sutta Piṭaka, and the Paramatthadīpanī in three parts on the Abhidhamma Piṭaka.
These ṭīkās or sub-commentaries were works containing expositions of points in the Aṭṭhakathās compiled by Buddhaghosa and other commentators, which needed further elucidation for their correct interpretation. There were ṭīkās compiled from time to time subsequent to the compilation of the commentaries, and what the council headed by Mahā Kassapa performed was the bringing of these various ṭīkās together and making a synthetic summary of them. Though the Saddhammasaṅgaha does not give any prominence to the part played by Sāriputta at this council, it is well known that several ṭīkās were compiled either by him or under his supervision."
—H.R. Perera, Buddhism in Sri Lanka: A Short History
Note: I left out a section about Sāriputta, but I will post that elsewhere.
R