When we try to create a new Access Type or edit an existing Access Type in the detail screen we see the below two options with same drop down values.
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Every Access Type is assigned an Access Level from Admin to None. Admin has the most rights, None the least. Ultimately Access Level is the level assigned to the logged on user.
Grant level is the security right of a logged in user to change the Access Type of someone in the contact table. These rights are as follows: