Can you please explain more why you need such a requirement ? What business drivers are this for ?
Generally an outbound run can have interactions with multiple channels like sms, email, push notifications etc and we could also have wait processing in offer/action flows which can do follow-up email, sms communications back to the customer.
So by design an individual channel delivery like sms completion does not always mean a outbound run is over.
Is it more to see if the SMS's were really delivery as a reporting need from the outbound run work object ?