This counts how many individual EIGRP acknowledgement packets were suppressed because the ack could be piggybacked onto an already-queued outbound reliable packet instead of being sent separately. This is essentially an efficiency counter -- a high value indicates EIGRP is successfully batching acks with outgoing traffic rather than flooding the link with standalone ack packets, which is good for bandwidth-constrained links. On a busy hub router exchanging frequent updates with a spoke, seeing this climb steadily alongside cEigrpRMcasts confirms EIGRP is efficiently piggybacking acknowledgements rather than doubling packet count.