I think the 150k is “the value you bring to the company” adjusted to “the location the company forces you to be at”.

If they demanded you to be in SF, one can guess a part of your comp was to adjust for crazy costs of living there. If you move away, that is adjusted.

Having been an expat, there are purchasing parity tables that are used in these relocations.

Imagine you were hired on Tulsa money and then forced to move to SF on the same amount...