Well bip47 does not require notification txn. If both parties online one just shares pm8 code and there is no need for notification txn Notification txn requires only if one party is offline you just follow each others paynym and use cahoots using soroban like in this video example of stowaway txn (payjoin) there is no need to make notification txn at all unless other party is offline or you know you will be paying same entity repeatedly when they are offline then use notif txn. Here video example inside wallet