In Illinois, your Workers Compensation settlement and award revolves around your wage. Low average weekly wage, low settlement; high wage, higher settlement.
You can count overtime if you get overtime on a regular basis, and if it is mandatory.
If you have a second job, you can also count the income from the second job toward the job you were injured on if your employer was aware of the second job.
You should tell your lawyer about possible ways your wage may be increased. You also need to check your records for W-2 forms, check stubs and other documents that support your wage history.