Please be advised that your Available Balance is the amount of money in the account that can be spent. It takes into account all transactions effected on the account (Debits and Credits). The Latest Balance on the other hand, displays the balance of an account but excludes any unbanked / uncleared transactions. For example merchants haven’t yet banked point of sale transactions or where deposits haven’t yet cleared (like cheques). The purpose of the difference is exactly the point – to show that there are possible transactions in play that affects your balance.