Revaluation of foreign currency balances to accounting currency calculates very high gain/loss

We ran "Revalue Balances" concurrent program to revalue foreign currency balances to accounting/reporting currency at year end, for a foreign currency customer receivables GL account.

The program created an unposted journal with a very high gain amount that cannot be explained.

We were expecting an exchange gain/loss of around $100,000 but systems has calculated $800,000 (a difference of 8 times)

We want to further investigate why the system calculated such a high gain amount. We want a breakup of the calculation ie which customer balances were revalued and at what rate. However no drill down of the journal entry created by program, is available.