Andreas Maurer wrote:
...
Yup. Always keep the AoA constant by using the flaps.
I think the procedure that is described in the ASW-20's manual
describes the physics very well.

Isn't the attitude rather than the AoA you are keeping constant?
As far as I can say from experience on LS6, it flies with nearly
the same attitude at high speed with negative flaps and at low speeds
with zero or positive flaps, which means that the Aoa (defined as the
angle between the direction of the airflow and the wing chord, i.e.
the line frm leading to (moving) trailing edge) varies.