Engineers make awful sales people

I had an interesting conversation today about the ability of engineers to be able to sell their services. As a one-woman band type consultant, I don't have the luxury of a sales force that markets my wares in an enticing way.  I rely heavily on referrals and the fact that  I do a great job in software testing. When I am asked for a quote, I like to base my estimates on value. What is the best value that I can provide at a reasonable price?  I think like an engineer.

However, I'm told that the best way to sell software testing is to focus on risk. How can you NOT afford to test?  I need to think like a sales person.

So, are engineers in general good analysts but bad sales people?