Of the three approaches, methods 1 and 3, using currency shares and empirics respectively to adjust for currency valuation effects, result in robust relationships between changes in currency-adjusted FX reserves and the BOP surplus, whereas method 2 using forex purchases as an alternative proxy for adjusted FX reserves is inferior.
It has to provide a greater than before consumer surplus to get the consumer to purchase the new products (or those things made by the new method of production).