A signal, message or auditory communication to arrive at understanding goes through several stages. These are duplication (hearing), discrimination (detecting differentials, such as between the sounds ‘b’ and ‘d’, identification (it’s a ‘b’ or it’s a ‘d’), association (these sounds add up to a word), onto understanding (the correct meaning for the word).
In other words the communication has to be processed correctly in order to result in understanding. That is why ARC is not enough, the raw data need to be analyzed, processed, evaluated in order to reach understanding.

References:

Auditory Processing Disorder | Dr. Angela Loucks Alexander

Compare Axiom 28 original and revised version.

Article: Why arc does not equate to understanding https://xscn.mgtconcepts.com/?p=724