Treatment Coordination (T1016) Billing - Client not Present

Hello - we have been billing Treatment Coordination (T1016 HN U8) for a handful of months and now want to look into billing this service when client is not present. 

I know that we are able to do this but have some questions I am hoping someone can provide some insight into:

1. Since the client is not present as long as it is noted appropriately it should not be seen as duplicate billing? i.e. the client is in group at the same time the TC is being completed without them present.

2. If TC is occurring through out the day in smaller increments can we bill for 1 unit if it totals 15 minutes? 

3. Any clinical documentation guidelines outside of the norm?

Thank you - Jeremy RL