CSP trained agents know how to work with lenders and how to present the offer to a lender that will make the lenders job easier and more likely to agree favorably.  Understand that there are hundreds if not thousands of requests for short-sales. 

If a lender sees a well presented and thorough package compared to a package that will need much time and attention, which do you think will get the preferential treatment?  Additionally, your CSP trained agent has connections with many lenders, local and national, and will understand the best way to guide your package through the system.