When keying in a Withdraw entry in an Investment account, (entering payee, date, type (for ex "EFT") and amount, the system doesn't save as you entered but saves the entry exactly as it did that LAST time you entered a withdrawal under that payee. You must go in manually and correct it by re-entering the correct data and resaving it.
It is easy to miss this; only to discover the mistake later when balance is off.
