For workflows to display on the settings>property>used in view, the field has to be specifically looking at a present, existing value for that property. In other words, the workflows are relying on checking that current value.
With the workflows that aren't counted with the property being "used," they are not relying on checking for a specific property value. In other words, these workflows are simply creating an action relating to that property, but they're not actually using that property's values. This means workflows making updates to this field are not displayed in the used in list view.
To me "used in" should display workflows that both referencing or checking that value AND/OR updating that value.
