Good question. It really depends on the data that comes from the brokerage firm. If the there is something in the symbol or source field then it can be associated with a payee in FN then it will be remember from month to month. But if there is only "Check" is just "cash" then nothing exists to associate with the transaction next month. If these transactions are different every month then the payee names will have to be entered. But the amounts, dates, status, etc will all be entered automatically. The memo can be filled in with the info from the broker.
Credit card charges are usually better than checks. The name or some source is passed for credit card charges. But this check sometimes the only thing is the check #. Look at the brokerage statement. Also look at the actual broker transaction file. You can see the actual data downloaded from the broker. This is the same data that is displayed at the top of the screen for the current transaction.