This is the 64-bit High Capacity counterpart to cnpdAllStatsOutPkts, again meant to avoid counter-wrap artifacts on high-speed interfaces where the standard 32-bit outbound packet counter could roll over between polling intervals. It matters specifically for outbound-heavy protocols on fast links; an admin graphing an interface running near line rate should always prefer this counter to avoid misleading sawtooth drops in reported traffic. Without using this HC object, a monitoring tool polling every 5 minutes on a saturated 10GigE port could see the plain 32-bit counter wrap multiple times and miscalculate the actual outbound rate.