FASB ASC 830-10-45-7 requires consistency in the functional currency defined for a given entity, but does allow for a change in the defined currency if a change in circumstances warrants such a change. In this event of a change in the functional currency, is the company required to restate previously issued financial statements in terms of the new financial currency?

Are measurement ring gains and losses considered to be extraordinary items? (see FASB ASC 830-10-45-19