This PerfCounter64 counter reports the average bit rate after rate limiting in the upstream (A2N) direction (measured after the flow's rate limiter, so it reflects the shaped, delivered rate rather than raw demand). An admin compares it against the subscriber flow's provisioned capacity to see whether traffic is running near, over, or well under what the port or flow is supposed to carry. If cmFlowHistoryABRRLA2N on flow 46 settles around 790 Mbps at the most recent completed bin, an operator sizing that flow for an upgrade has a concrete number to compare against its provisioned limit, rather than guessing from aggregate port utilization.