The CO adjustment feature is an excellent thing. It can be a great way to fix a rough or high/low idle, but one needs to consider that what it actually changes is the pulse-width across the entire rev range. IMO if you need to go more than +/-5 for a better ride, then the map needs tweaking. If you have to go more than +/-10, then you need a new map entirely. For idle, +/-3 should be more than sufficient. If your idle is smooth and the ride is good, but you feel a slightly higher idle RPM would be nice, there are ways to diddle the map to get it to idle where you want.