If you are talking injury compensation: Current net income, does not account for future potential increase of income. But, it also doesn't account for future decrease of income, because you lost a job, and had to take a lesser paying one. If your talking about some other kind of compensation, SS, Workman's Comp, etc, it should be tied to gross wages.
The net income not good metric to tie compensation to because it does not get meaningful on an individual basis. In a work-place environment, both the employers who work hard and those who don't' still get rewarded.