Alan,
We should stop guessing about what the RadarBox hardware and software does and what it does not. My initial post was information for the AirNav team. I am sure their developers are able to understand the information and are able to use it for their implementation.
I also don't want to analyze what causes incorrect data that is posted in other forums.
I simply wrote about what I realised using the two different receivers I own (and I cannot tell anything about other receivers).