While you are waiting for your approval do not be afraid to call your insurance 2-3 times a week. Don't be a pest but keep on them. I found out on 9/22 that I was denied because I called them. I wouldn't not have found out until 10/2 if I would have just waited for the letter. So since I already knew a second letter has been submitted and they have now requested additional information. Out of the 4 things that they have requested 2 of them are done and the other 2 will be done Monday night, 10/6. It is so worth calling them. (I also keep a call log)
Just thought I would share.