It depends of the design, but I think generally it takes me longer to design mockups than to implement them.

When implementing you know what you should do, and when know your tools, you can pretty much do it as fast as you can type.

When designing you start from scratch. You try to wrestle all the ideas and requirements with the best practices and the right style, to create something that's new and works.

So I think designing well is much harder than implementing the design well.

The article was about design, not implementation.