My first bit of advice to you is to get an attorney. It will pay off in the long run. Secondly, if you pay for a second impairment rating out of your own funds and it comes in lower than 5% simply don't use it. However, if you ask the insurance company to pay for it your stuck with the results. Sorry, but I am in your shoes and I hired an attorney...

http://www.state.vt.us/labind/wcindex.htm

http://www.state.vt.us/labind/wcomp/doctorsppd.pdf