According to the TimeCardView App information, it only supports 8 IP phones.
"Maximum Sessions Maximum number of TimeCardView sessions, either 2 or 8, depending on the platform."
In Lab 11 "Smart Application:TimeCardView" document I can see we can purchase additional user licenses for the timeclock viewer
All UC500 units include up to 8 free seats of TimeCardView, additional TimeCardView licensing per seat.
SKUs for TCV 7.0.x: SW-TCV-USER‐1= ($US100 list)
SKUs planned for TCV 7.1 and up using Cisco Licensing: SL-TCV-USER‐1
Maximum of 64 users can be enabled for TimeCardView, based on Voice Mail user limit.
Is that 8 phones total or is that 8 phones attempting to use the time clock at once?