This is the byte-count version of cpwVcPerfCurrentOutHCPackets, counting total bytes this router has sent into the PSN for the pseudowire within the still-accumulating current interval. It lets an operator see near-real-time whether outbound traffic on a specific VC is approaching a provisioned bandwidth ceiling before the interval even finishes. A sudden jump in this counter mid-interval, disproportionate to the packet count, would suggest something on the VC started sending unusually large frames, like a jumbo-frame misconfiguration.