My impression is the Brew Boss App does not play well with other things on the tablet. I have a single cheap tablet I bought from Amazon that has a sole purpose of running the Brew Boss Software and doing nothing else.
A little while back I had Angry Birds, Plants vs Zombies, and some other misc apps on the tablet and was experience what I can best describe as temperature lag. The Brew Boss controller directly reading from the pot would show that the temp was 152, where as the tablet would still be showing it as 143. By the time the tablet got to 152 the controller was at 164.
Basically it was vastly overshooting the temps. Though a couple of e-mails and pictures with Darin, I figured out that uninstalling the extra apps the controller worked fine. However it does not seem I can use the tablet for much else.