Did anyone ever find the answer to the OP's question? It would seem, to me, that when you have "notified" the computer that you switched from the tank with the transmitter to a tank with no transmitter, the computer would stop displaying any pressure/GTR info. That is the only thing that makes sense. Otherwise, conflicting, irrelevant, and perhaps dangerous information could be displayed (ie, giving the impression of valid gas information based on a tank no longer in use). it would be a highly unsafe way to manage the display and I can't imagine Shearwater would allow gas information to be displayed once the computer "knows" from the gas switch that you are no longer breathing from the tank with the transmitter.