For a chainsaw engine under load there is one and only one correct fuel mixture: just slightly richer than max power in order to to have a safety margin. Anything else is losing power, wasting fuel and/or risking engine damage. These simple systems are adjusting for that point regularly just by varying the mixture and watching the rpm change. You cannot increase power by feeding it more fuel, and you cannot reprogram the feedback system for more power (so who cares about the code?).
A conventional carb can be adjusted to give a correct mixture for at best two rpm points: idle and at some specific high rpm. At every other rpm it is wrong, usually rich but possibly lean as well. If you have no accelerator pump then you have to set the idle too rich as well so it will accelerate. This has nothing to do with the skill of the tuner, it is inherent to the way the carbs work and is simply the best they can do. The feedback carbs can do better, keeping the mixture correct as the rpm changes - a conventional carb cannot.
I understand that some find these things intimidating, but most kid's toys are more complex these days. Troubleshooting them is not a big deal, and people have had no trouble replacing the bad fuel control actuators that Stihl had. The number of people on this board that actually understand how the conventional carbs work and can diagnose them is quite small, most just replace parts and hope. Just like the conventional carbs the feedback ones are cheap, simple junk (they should not be expensive). They will have defects, failures and wear out, as will all things electronic, mechanical or even biological. Nothing lasts forever.
