Yes, you can edit a bank account from the reconciliations tab OR the chart of Accounts tab.
The statement balance is the sum of all unreconciled and reconciled statement lines, not taking into consideration deleted statement lines.
The Juan balance is the sum of all the transactions that use the bank account as a payment account.
The two balances might not always be equal. For example, the balances will not match if the value of the statement lines imported is higher than the amounts of all available transactions in Juan.
Clicking on Juan Balance will bring you to the Cashflows page, only showing cashflow transactions involving the payment account.
