With a bilateral tax treaty exists between 2 countries in international investment, I think the effective tax rate that a company must finally bear is the higher tax rate between 2 countries each year.
So in the case of Imoni Co, the final tax rate in year 1 and year 2 is 20% and but examiners did not calculate taxation on positive income of Imoni Co in year 2 (after deducting loss carried fw of year 1)