What these systems don't tell you is that for best results, you should have a patternmaking background. The Lutterloh and Dusan systems help you draft a sloper, from which ALL garments are made, then design your garments by tracing the sloper, then manipulating it to get your design. If you don't know the principles of patternmaking, all you have is a dress with a waist seam.
My students made slopers first by hand, then in the computer. They were taught to manipulate them. We used Jack Handford's book for the slopers, then the Armstrong book for design. They also learned how to add/subtract from the sloper to make dancewear, swimwear, jackets and coats. Once you have a sloper that fits, a patternmaking book helps to design.