When the ICMP reply packet is generated in CPM, its FC is set by default to NC1 with the corresponding default ToS byte value of 0xC0. The DSCP value can be changed by configuring a different value for an ICMP application under the config>router>sgt-qos icmp context.
When the packet is forwarded to the outgoing interface, the packet is queued in the egress network queue corresponding to its CPM assigned FC and profile parameter values. The marking of the packet's EXP is dictated by the {FC, profile}-to-EXP mapping in the network QoS policy configured on the outgoing network interface. The ToS byte, and DSCP value for that matter, assigned by CPM are not modified by the IOM.