I really like how you differentiate between Work-In-Process and Work-In-Progress. It makes so much more sense and I’ve never thought of it that way. I would actually move that right up to the first time you speak about it.
However, I’m finding the concept of postponing the start of work you explain on p.43 hard to buy into. My perspective (p.45) is that it is not really about starting work later, but one-piece-flow (i.e. stop starting and start finishing what you started) and limiting work in process to keep the throughput stable and predictable.
It might convince me if you started the section with a case study or the benefits listed. Explain in a case study that I can relate to (i.e. not abstract idea but a tangible example) and only then analyse why it worked with all the graphs and explanations.
I’m pretty sure you have a very good reason to believe that postponing work is beneficial, but I’m not seeing this benefit from reading this section. I understand the explanations, but I’m missing the benefit.