Initially when I saw this open salary approach and especially the calculator I was intrigued. But you cannot make salaries into a formula and get 100% good results.
The approach Basecamp (37signals) has with picking a location, then paying people based on 95% percentile (top 5%) market rate regardless of where they live is just much easier to explain to employees than some arbitrary multiplier thing that just leads to endless discussions.
https://m.signalvnoise.com/how-we-pay-people-at-basecamp-f1d...