There is only one reason tuning boxes are adjustable
To allow you to find the optimum power setting for your engine.
Once you have found the optimum setting there is no reason to change the settings again
Engines, even if they are the exact same model, do not all product the same power from the factory.
The differences will depend on the model but a 5% different is possible in engine power between supposedly the exact same models.
And this is why tuning boxes are adjustable. Some cars will be able to run more aggressive settings than others and likewise, some cars will have to run less aggressive settings than others.
Whatever the case, once you have found the optimum setting for your engine, this is no reason to change the setting again.
How do you find the optimum setting?
Install the tuning box with the factory settings, drive the car for a few days and gradually drive the car harder and harder, if you get no check engine lights, repeat the process with a higher setting.
When the cars performance does not improve, you get a check engine light or generally you find the engine less happy, reduce the setting to a know good setting.
Tuning boxes are not meant to be adjusted
ie adjusted regularly, there is simply no reason.
If you want to change the characteristic of the engine and/or reduce the responsiveness of the engine fit a pedal tuning box. A pedal tuning box is designed to be adjusted regularly to suit the road conditions.