question about exception letter

Hello all!
I spoke with an excelsior rep today about the program. I was going to wait until I passed NCLEX to apply, but i heard about the ACE approved credits being limited after the 1st of October, so I think i should hurry. The rep stated I should have my credits transferred ASAP, so I requested them today. Since I have not sat for my boards yet ( i test in October) he said I can write a letter of exception to push my eval of credits through. I have no clue on what to write. Do you guys have any advice? Also i have seen on here that you can take 1-2 exams before enrolling.. is that to save money or to see if you would like the program? I was all fine and dany studying to take my boards and ran into a post talking about this change.. Now I cant think of anything else. Any info would be greatly appreciated. Thank you very much