First we are talking about retained earnings, a balance sheet position. Method is current rate method.
As I stated above, once derived from P/L by applied average rate (upon mentioned method), current earnings in next period becomes retained earnings. Who works in preparing FS, he knows that re-booking is required from current period to retained earnings account. Once re-booked at new BS equity position, for further translation procedure, current rate at BS date should be applied. Ex. at 01.01. USD/EUR is 1,2, at 31.12. USD/EUR is 1,4 and one of those currencies is reporting currency, another is local (entity) currency.
Let’s see what IFRS says:
Summary of SIC-30
SIC-30 addresses how an enterprise translates items in its financial statements from a measurement currency to a presentation currency. SIC-30 provides that when the measurement currency is not the currency of a hyperinflationary economy, the requirements of SIC-19.9 should be applied as follows:
assets and liabilities for all balance sheets presented (including comparatives) are translated at the closing rate existing at the date of each balance sheet presented income and expense items are translated at the exchange rates existing at the dates of the transactions equity items (other than the net profit or loss for the period that is included in retained earnings) are translated at the closing rate existing at the date of each balance sheet presented all exchange differences resulting from translation should be recognised directly in equity.
http://www.iasplus.com/en/standards/sic/sic-30
Let’s say what says US GAAP
If the functional currency is the home currency, the current method is used. The current method translates all assets and liabilities at the current spot rate at the date of translation. Equity items, other than retained earnings, are translated at the spot rates in effect on each related transaction date (specific identification). Retained earnings are translated at the weighted-average rate for the relevant year, with the exception of any components that are identifiable with specific dates, in which case the spot rates for those dates are used. Income statement items are translated at the average rate for the period, except where specific identification is practicable. The resulting adjustment is not recognized in current earnings, but rather as a component of other comprehensive income. -
See more at: http://www.eisneramper.com/Foreign-Currency-Translation-FAS-52.aspx#sthash.V6FIkiGi.dpuf
OK, Magician, regarding US GAAP, you may be right but USGAAP are standards which are not reality for the most of the world 