I don't think you're right here. It may be true that you have to pay extra for hotspot functionality, but I don't think that any of the data between the slave and the master gets counted as hotspot data, since it all stays within the LAN generated by the hotspot. I set up the hotspot on the slave to use this app, and the slave has no internet access at all (doesn't have a SIM).
BTW - if it is true that the bits are counted, two things (a) I thought the government told VZW they could not do this on "Limited Plans", and also, (b) isn't there a utility out there PDNet+ that is supposed to avoid this sort of thing?
Can you please explain your setup to me that you have working? Do I need to run AAGateway on the Master and the Slave phones? I'm thinking no. Does the Master have to both expose both a hotspot and run a head unit server from the development menu of AA? I'm thinking yes. What is the order of startup here, and can the stuff on the Master be automated? Are you running the Alpha or Beta versions? Thank you for any help.