How to compare previous salary with current salary of person in Object Validation Rule Type

Summary:

Hi Team,

We have a requirement where we need to restrict manager from submitting 'Change salary' action without making changes to the salary.

for that we have created below highlighted rule logic, its working fine for some direct reports, and for some is not works as expected of same manager,

please suggest if you have any ideas on this or any other alternative logic to compare the previous salary with current salary.

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21D

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