Profile Matching Criteria works on the configuration setting provided by the plugin.
In order to configure the settings, navigate to WB Plugins >> BuddyPress Friends and follow suggestions
Starting Percentage: This field shows the default matching percentage. For example, if you have set 20% in this field then the calculation will start from this value.
Let’s suppose you are visiting a member’s profile and none of his profile fields match yours. Then default matching percentage will show up there in the member header i.e. 20%.
Profile Matching Calculation: Now if you have set the profile field and their calculation percentage, now the profile matching will be calculated based on that calculation. Let’s suppose if the URL and nickname profile fields are matched with another user, then a 40% profile match will show up there in the member header.