Hochkurz is a bit of a special case, it was primarily developed to avoid the need to do decoctions.
It is well suited to achieving the steps with hot water additions.
I was referring to using the element in a tun to achieve steps like most of the commercially available 1V systems. Having the malt in a pipe means the heated wort can be pumped through the grain bed from either top to bottom or bottom to top in a Braumeister. With a bag its virtually imposable to get even distribution of the heat as the wort will take the shortest path (usually out the sides) and you will often end up with bits of the grist at very different temperatures. Means in efect that you can have several different mashes going on at the same time.
Makes repeating the process difficult among other things.
In any system the application and distribution of heat is probably one of the most important design variables, if that is you aim to have controll of your process and achieve reasonable repeatability - make a good beer again...
Mark
Good basic info on
Hochkurz scroll down a bit from the top.
M