Does author in search of book sales need book promotion services?

Here's an email that I received recently from an author:

This is my recent book [here, the author inserted the URL for his new title]. What can you do to make it sell better?

My response to him (and to other authors and publishers who approach me with the same question ) is:

Although I don't get involved in book sales, you might be interested in the book promotion services that I offer. If you haven't already visited the "services" page of my site to get a sense of the traditional and online book publicity services that I offer, I'd encourage you to do so. I'd be glad to provide a customized book promotion plan upon request, so let me know if you'd potentially be interested in what I offer. Although book promotion is tangentially related to book sales, it is not the same thing, and there's no guarantee that even the most successful book promotion campaign (which is designed to build the author's brand and raise the visibility of the book) will result in increased book sales. Although it often works that way, I wanted to draw the distinction for you between the two, because you may be seeking a book distributor rather than a book publicity firm. Let me know if you'd like more information about any of my services, once you've reviewed my offerings.