I can't believe people pay money for this. Anyone even thinking of paying for Feng Shui consulting should watch the Penn & Teller BS episode on it and see how different consultants claiming to be using the same core theories had entirely different designs to maximize the energies. Just hire a good designer, maybe even one who has studied the design aspects of Feng Shui (basically it could be just called the Tao school of design, but it includes concepts known to every architect and designer), and forget about paying extra for the hooga booga.
It is money well spent by a developer if an area has a large asian population. The developer can make minor changes that won't be noticeable to no feng shui buyers but will be huge to those that do use it as a guide to their life.
The validity of feng shui is irrelevant - the only thing that matters to the developer is whether a significant portion of potential buyers use feng shui for their buying decisions. In Salt Lake City it probably wouldn't be an issue but in California and other areas with large asian populations it will.
The Feng Shui craze in the SF Bay Area has to do with "contacts" and "networking".. a prestige and a "who you know means who you are" kinda thing.