Graphic Design Pricing

Many Graphic Designers can often do the work.  They can talk to their clients and often come to conclusions on what the client wants.  However I, and many others, have trouble pricing their designs at a reason cost for both ourself and the client (obviously).  I stumbled along a post by a designer named David Airey, who lists his way of calculating the costs for the client.  He does this in a way that not only makes sense mentally, but visually as well. I apologize in advance for the poor image quality, the photo was configurable.

http://www.davidairey.com/design-pricing-formula/