Quality control issues-curiosity

What would you rather have 100% QC after the MH is built or QC in the design/built of the product? I think what most people don't realize is that most of these problems that we talk about here are caused by the way these things are designed/built. An example would be my window that leaks and when I removed it I found out the opening was cut out by hand and not a template or NC machine. The opening was irregular and I had to shim the window to get it to seal. If a template or NC machine was used the opening would be consistent. It is hard to blame these workers when they have to layout thousands of holes and cutouts by hand rather than using production tooling. It is hard to amortize tooling when few MH's built. You don't find these same kinds of issues in the auto industry because of the quantities built and the production tooling used. You either have to design and build with production tooling/automation in mind or have very skilled craftsmen that never make mistakes. I don't know who makes the most identical units per year but I would choose that model over a custom built one of a kind MH. Not only would the price per unit be cheaper because of the increased quantities and the learning curve but they can afford more production tooling to built these units.