Okay, how should it be graded? What's preventing me for arbitrarily choosing a number like 100 months? Averages might not be perfect, but at least everyone can agree on it.
You can choose 100 months then advocate your position on its merits, if you like. This is a political question, a contest of power and resources, not a math problem. Scaling severance to be proportionate to the average period of unemployment at the time of firing would ensure the company doing the layoff would bear their share of the societal burden of unemployment they are helping to create.
>You can choose 100 months then advocate your position on its merits, if you like
You certainly didn't bother to do that, and "2 months is generous because it's above average" might be a lazy argument and perpetuates the status quo, but it's certainly orders of magnitude better than no argument.
Your system of averaging employer input means that exclusively employers comprise a virtual senate for all matters severance and the corresponding employment they create.
Any proposal that considers opinion and interests beyond businesses’ is already more even handed than your proposal.
When I got laid off from GE I received a severance and bonus. They trained me on how to apply for unemployment so that my severance wasn't calculated. So I got unemployment and was able to bank my entire severance. If you follow the instructions without the help of legal advice your unemployment starts when the severance runs out.