A clinician may be working with a client through a 3 hour session and during the appointment, the client may be having difficulty with heightened symptoms.  In spite of the clinician's attempts to de-escalate whatever situation has caused this, they determine the client should be assessed at the hospital.  The clinician talks the client into going with them to the emergency room and they go to the hospital where there is typically a long wait time.  This appointment could easily stretch beyond the 5 hours allowed for 2 units.  There are also times, especially when a client initially comes into services, that a client requires more time as there are significant needs that may take longer than 3 hours to address.