Makes sense and thanks. Sounds like the kind of capability that gets very expensive to include late in the game. Which speaks to a problem with contemporary culture at Boeing, which was to get rid of the test and QA roles that would typically catch these issues early enough to incorporate the solution (3+ thermostats) back into the design before it got too expensive to do so. Microsoft, btw, is guilty of the same test & QA culture dilapidation, which results in the crap Windows we get nowadays.