"Adjusting round corners for a button in photoshop is easier then[sic] adjusting border-radius in css"
Actually, in CSS it couldn't be more simple... border-radius: 5px;
This makes me wonder if the author thinks we should be chopping images for rounded corners?
"This process is executed in a linear fashion starting with information and ending in code, but requires iteration loops at each step."
A good web design process is an active collaboration between designers and developers, not hand offs. I'm a firm believer that design should be coded early and often in order to uncover design issues that can't be detected on paper.
It's fine to break things out into steps, however, they should be iterated as a whole instead of individually. This way issues found in one step have a chance to feedback into previous steps.