Why doesn’t the manufacturer just set the vehicle to the optimal value?

The manufacturer builds a car for the global market. In other countries, the fuel often doesn't correspond to our quality norm. Furthermore, continuous running at extreme heights can impair combustion. These, of course, are characteristics that do not have to be taken into account in Europe. The manufacturing tolerance can also be a factor. When the vehicle is on the test stand after production, the output might have to be boosted somewhat. That’s why tolerances are necessary.