In 1482 the Muromachi bakufu (shogunate) requested that he pay taxes for Oki and Izumo Provinces for which he had been exempt on behalf of his father; however, Vice Shugo (Governor) Tsunehisa AMAGO did not follow this instruction and the following year Masatsune received a command for the ruling families of Izumo to banish Tsunehisa and a new vice Governor, Kamonnosuke ENYA, was dispatched to Gassan-Toda Castle.
1482年（文明14年）に室町幕府から、出雲と隠岐において父の代から免除されていた税を要求されるが、守護代の尼子経久がこれに従わず、政経は翌々年に幕命を得て出雲の豪族に経久を追放させ、塩治掃部介を新たな守護代として月山富田城に派遣する。