I filled I539 online to change my status from H1B to F1 on April 20. I sent in my supporting documentations and received hardcopy of receipt shortly after. My question: When I prepared my supporting documents I did not elaborate on the cover letter why I want to change my status. I just simply listed all submitted supporting documents. When I got my I-20, the checklist stated that the cover letter is optional, so I did not worry too much about it. Now, I read everywhere how important the letter is. Any thoughts about how likely this might cause a denial. Also, should I sent a seperate cover letter to "complete" my application or should I simply wait.
My I94 expires in August 2010 and I am still employed. If I am denied, could I just sent in another I539?

Thanks