Source-currency preservation finance

The simplistic way to handle multi-currency is: convert everything to the functional currency upon receipt and only store the equivalent. The problem: when payment arrives three months later, FX gain/loss cannot be recalculated because the original data is lost. Source-currency preservation means storing three pieces for every monetary line: amount in original currency, currency code, and applied FX rate. On payment receipt, it is revalued against the day’s rate and the difference recognized as financial income/expense. It is an obvious pattern, but many ERPs implement it poorly — especially those that evolved from a mono-currency architecture. cifraHQ Enterprise was born multi-currency: even a local USD invoice carries explicit currency fields.