How many models do you need for effective fiscal policy?

A recent TA from ADB for Indonesia;
Indonesia: Social Security Reform and Economic Modeling Capacity Building;

-enhance and develop an analytical framework for each macroeconomic sector,including real, monetary, external (balance of payments), and fiscal;
- based on (ii), develop an analytical macro model to produce a macroeconomic
outlook;

-upgrade the computable general equilibrium model of the Indonesian economy, previously built in FPO to quantify economywide effects of introducing SJSN programs and improved labor market flexibility;

-work with the international macroeconomist to refine the budget model to assess the
macroeconomic risks affecting the budget;

-work with the social security policy specialist to develop pension models and
analyze the fiscal impact of social security reform