A client id for every transaction is one of the most important parts of proper IOLTA / escrow account bookkeeping.  Without a client id for every transaction, it will be impossible to perform a correct three-way reconciliation of the account.  A proper three-way reconciliation requires: (1) the main register balance, (2) the total of all individual client ledgers, and (3) the adjusted bank statement balance.  

All bookkeeping programs work one of two ways.  Transactions are either entered into a main register and sorted into individual client ledgers or transactions are entered into an individual client ledger and merged to create a main register.  If transactions are entered into the main register, the client id is used to sort and create the individual client ledgers.  If transactions are entered into the individual client ledger, the client id is used to access the proper ledger to enter the transaction.