When a forwarding class is redirected to a forwarding plane queue group queue or policer, the packets sent to the queue or policer are statistically tracked by a set of counters associated with the queue group queue/policer and not with any of the counters associated with the SAP.
This means that it is not possible to perform accounting within a queue group based on the source SAPs feeding packets to the queue. That is, the statistics associated with the SAP do not include packets redirected to a queue group queue.
If the user enables the packet-byte-offset {add bytes | subtract bytes} option under the ingress queue-group policer, the byte counters of that policer reflect the adjusted packet size.
The set of statistics per queue are eligible for collection in a similar manner to SAP queues. The collect-stats command enables or disables statistics collection into a billing file based on the accounting policy applied to the queue group.