When making recordings of g729 channels at least two decoders will be used. This means that if you have 10 licenses you can have a maximum concurrency of 5 calls going through your system that is being recorded. For anything but the smallest of switches this is not acceptable.
In addition, recording to .wav is a rather space-consuming process. Instead, we’d like to minimize the g729 license usage, as well as optimizing disk-consumption.