Settlement negotiations required skill and experience. I previously made an observation and say there is no formula or easy answer that can substitute for the advice of an experienced work injury attorney. You need to sit down with a professional lawyer who handle legal negotiations ever day to get the most potential settlement.
See my prior answer which is just the tip of the iceberg on the calculations for a "lifetime" settlement.
Good luck to you.
NOTE: This answer is made available by the Illinois lawyer for educational purposes only. This observation is not like a communication with a lawyer with whom you have an attorney-client relationship along with all the privileges that relationship provides.