We probebly "too good for QoS"
And probebly 80% of the company I know if they keep the Core net without traffic congestion.
The Voice has private VLAN and the the phone put some ToS or l2 .P marking but that Voice VLAN is not getting any priority on the Core net.
It's take from 4-10 ms to get to the IP-PBX or Voice switch so why should we have any quality issues?
/SJA