I second what Steve wrote about using an attorney. I can only speak for myself and the offer I received. I have no opinion on other's choices. But the attorney I visited quoted me $1,500 for the first year, then $750 for years 2 and 3, for a total of $3,000. Of course, paid out over 2 years, the present value would be slightly less, but not much. This is still a decent amount of money.
I would suggest that anyone thinking of using an attorney consider the cost over the entire process.
As I looked over the project, I realized that the attorney's work would only comprise about 10% of the effort. I had to procure all my own documents, get it all down here, fill out all the forms, visit all the offices, pay all the fees. In other words, the amount of work that was being outsourced for $3K was about 10% and I was still assuming 90% of the workload. No thanks.
Now that I almost have everything in order, re-application in years 2-3 will be a cinch (provided nothing changes on the legal side). Also, I negotiated with the US attorney that my fee includes a similar inome verification letter for future years. So the small payment I make today will be the only one.
Admittedly, I have stepped in a pothole or two along the way. Nothing serious, but it has taken some time and effort to untie a few knots in my application. I can appreciate the time and energy savings that one would render from the use of an attorney. Different people, different choices.