Allied Telesis AT 8000/8POE - Manual (Page 136)

Chapter 10: Quality of Service (QoS)
136 Section I: Using the Menus Interface
One last thing to note is that CoS does not change the priority level in a
tagged packet. The packet leaves the switch with the same priority it had
when it entered. This is true even if you change the default priority-to-
egress queue mappings.
The default setting for Quality of Service is disabled. When the feature is
disabled, all tagged packets are stored in the lowest priority queue of a
port.