Is this the correct way to do a daily maintenance cost

rail_infrastructure_efficiency.nut

		local infrastructure_count = GSInfrastructure.GetInfrastructurePieceCount(company, GSInfrastructure.INFRASTRUCTURE_RAIL) + GSInfrastructure.GetInfrastructurePieceCount(company, GSInfrastructure.INFRASTRUCTURE_SIGNALS);

		local vehicle_list = GSVehicleList();
		vehicle_list.Valuate(GSVehicle.GetVehicleType);
		vehicle_list.KeepValue(GSVehicle.VT_RAIL);
		vehicle_list.Valuate(GSVehicle.GetProfitLastYear);

		local maintenance_cost = GSInfrastructure.GetMonthlyInfrastructureCosts(company, GSInfrastructure.INFRASTRUCTURE_RAIL) + GSInfrastructure.GetMonthlyInfrastructureCosts(company, GSInfrastructure.INFRASTRUCTURE_SIGNALS);
		local profits = 0;
		foreach (vehicle, value in vehicle_list) {
			profits += value + GSVehicle.GetProfitThisYear(vehicle);
		}
		local current_date = GSDate.GetCurrentDate();
		local current_year = GSDate.GetYear(current_date);
		local days_since_last_year = 365 + current_date - GSDate.GetDate(current_year, 1, 1);
		local efficiency = infrastructure_count > 0 ? (profits - maintenance_cost * days_since_last_year / 30 ) / infrastructure_count : 0;