 From April 17, 1871 to 1878, Ostrovsky was Associate State Comptroller.He was assigned to perform audits in Vladimir, Tula, Kaluga, Yaroslavl, Kostroma, Pskov, Vilna, Grodno, Kovno Province, and the former Kingdom of Poland (then a Russian possession).In 1877 he performed a field audit of the Caucasus Army.