This counter tracks the number of attempts by this SU to transmit data PDUs directly in contention data slots that did not receive the expected explicit acknowledgment from the headend, triggering a retransmission. Admins use a rising retry count as an early sign of upstream contention or RF trouble, before it escalates into outright dropped data. For example, an SU with elevated cwdIfSuServiceTxRetries but low cwdIfSuServiceTxExceeded is still getting its data through eventually, just with more retries than normal, which is worth monitoring before it worsens.