It doesn’t make since to out source your supplement. You can just as easy document any line items the adjuster missed. Use programs such as xactimate or Estimation Pro to build professional supplements, and submit them to the insurance company. I have yet to see any insurance company not except either form.
Farmers Universe states that 94% of 2008 hail & wind claims where supplemented. So learn your allowable expenses “each insurance company has its own criteria” and bill for them. We bill for every thing we do on a job and let the adjuster sort it out.

You will find that you can easy increase you project 10 to 20 percent.