I'm not sure anyone really knows the exact answer to your question. Take this for what it's worth because this is only what I have heard and I by no means know nothing. The HR email will trigger another review but it's my understanding that it will not be re-tiered. Once they give it a score its not likely to change much. I'm in the same boat, my app was scored and I wish I had gone over it with a fine comb to make sure it was perfect. I have since made it to be about as good as it can be. I have even had a recruiter look at my app and she loved it too. I have had several people send a letter to HR on my behalf causing it to be reviewed again but unfortunately for me, I'm still waiting since it has already been scored. Maybe my app still isn't good enough but from what I have heard, you want your app as good as it can be when they review it for the first time. Jim Graham told me he had an app that spelled magna cum laude wrong so he said he didn't believe him since he couldnt spell it right. Definitely have them send a letter on the chance it gets screened again and has what they are looking for but be prepared to hear nothing if it doesn't meet what they are looking for or if your score doesn't change. Again I am not in the know so this is just hear say!