The value knob has a few options.
The value knob can adjust three things. BARO, Heading Bug, and the Altitude bug.
In setup, you can adjust which one of these happens first. So turning the knob will adjust either BARO, HDG, or ALT right away. To get to the other settings, you press in the knob and it cycles through. The current thing being adjusted and the value for it is displayed on screen.
The second option is if the knob does nothing without a push first. If you this is turned on, you must first press in the knob to adjust your first option, or press again to toggle though the other options. If this is not turned on, the instant the knob is turned one click it will adjust your first option.
We did a lot of work with our beta customers on this behavior and many of them had the same concern you did. They all appear to believe this set of options gives each customer the ability to trade off ease of access with accidental adjustment protection.
