The Fidelity Curve: How to weigh the costs and benefits of creating UI mockups
Ryan Singer

I think what you’ve not handled here is that the time taken to build the “real code application” will not be a fixed length.

With a very quick mock, you may hit more problems, need to rewrite more code and end up with a less-clean solution that’s harder to maintain.

With the more in-depth mock, you discover more of these issues during the creation of the more complex mock — and even though this mock takes longer to build, you may be saving time and increasing quality in the final real code build.