Hi Arunas, hi Ron,
I would say this calculation is a bit "optimistic".
For 120kbit/s I end up at roughly 65MB per hour, for the higher quality codecs where you will have about 230kbit/s 100MB per hour.
As there was a thread about the usage of VOX some days ago. If you change the setup to constantly stream the the TX audio then you will have about twice the data volume.
vy 73, Simon (DJ4MZ)