Total defoliation needs to include removing every primary tip. I think that's what you mean by, "...It works very well. But only in this combination!"
If the tip is not removed, there will be less back-budding, a lot less, and none in some cases.
Hedge pruning works for Walter because of the shape of Walter's trees. It is less useful for formal uprights that have layers and substantial open space between layers. The size and shape of the open spaces is what needs to be maintained, so internal back-budding is a secondary function that accrues in reducing the size of foliage via defoliation, and cleaning out back-budding that grows into the open spaces is just part of the job.