There is the "fairness" argue for this ("it doesn't matter where the employee is, they create the same clause for the company") however with taxes etc. being di

There is the "fairness" argue for this ("it doesn't matter where the employee is, they create the same clause for the company") however with taxes etc. being different it isn't equal on that level, and whether it is really fair that people in different locations get different value is a complex philosophical question :)