Not sure how the MB one works. But the Ford setup works like this. There is a restrictor "valve" at the pump. During full assist the valve is backed off allowing full flow. As speeds increase the ECU commands the valve to start closing off fluid flow and thus reducing assist.

Most thought it worked the other way, that at low speeds it was working to provide more assist. But it only does its thing to reduce. So if one unplugged the valve on a Ford it would be full time assist.

The only way to make full-time low-assist steering would be to install a potentiometer and control the valve manually. Just prey you never, ever have to avoid an accident!! The Ford system, at least, monitors steering wheel movement and at higher speeds when assist is reduced it will return some or all power during quick movements, such as to avoid a deer.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car