Which equipment are you using ? I know about call drop due to remote transcoder in alcaatel system, but it might not apply to your case.
QoS indicators are not standard… They all differ among vendors.
If it’s alcatel, then yes, the call drop due to remote TC clearly impacts the subscriber. This kind of call drop is not necessarily due to the transcoder itself, but rather a faulty ABIS link (intermittent connection) or BTS/BSC problem (faulty TRE or SUM board).
It can also be due to some faulty boards in the TC, but that’s quite rare. It’s easy to detect, because it impacts ALL the cells of the TC.