How to correct the home currency value for foreign bank account closing balance? Thank you.

The apparent discrepancy is the result of changes in the exchange rate during the year, and transactions that are not recorded at the actual exchange rate at the time of the transaction.  Failing to enter the home-currency adjustment at year-end is one contributing factor.  Note that this apparent discrepancy is just a result of doing business in multiple currencies at fluctuating exchange rates - it is a natural consequence, it is not an error.  The year-end home-currency adjustment records the result of the differing exchange rates - a gain or loss.

At a minimum, a home-currency adjustment should be recorded at every year-end.  Failure to do this may result in misleading financial and tax reports, and errors in tax payments.  For some businesses it may be desirable to record a home-currency adjustment more often - quarterly, monthly, immediately following an unusually large transaction, or on some other criteria unique to your business.  

You should discuss this with your own professional accountant to help determine the best course of action with respect to the previous year-end currency adjustment, the current year-end adjustment, and the most appropriate timing of adjustments between year-ends.